1
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He Y, Kennes DM, Karrasch C, Rausch R. Terminable Transitions in a Topological Fermionic Ladder. PHYSICAL REVIEW LETTERS 2024; 132:136501. [PMID: 38613303 DOI: 10.1103/physrevlett.132.136501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 01/24/2024] [Accepted: 02/02/2024] [Indexed: 04/14/2024]
Abstract
Interacting fermionic ladders are versatile platforms to study quantum phases of matter, such as different types of Mott insulators. In particular, there are D-Mott and S-Mott states that hold preformed fermion pairs and become paired-fermion liquids upon doping (d wave and s wave, respectively). We show that the D-Mott and S-Mott phases are in fact two facets of the same topological phase and that the transition between them is terminable. These results provide a quantum analog of the well-known terminable liquid-to-gas transition. However, the phenomenology we uncover is even richer, as the order of the transition may alternate between continuous and first order, depending on the interaction details. Most importantly, the terminable transition is robust in the sense that it is guaranteed to appear for weak, but arbitrary couplings. We discuss a minimal model where some analytical insights can be obtained, a generic model where the effect persists; and a model-independent field-theoretical study demonstrating the general phenomenon. The role of symmetry and the edge states is briefly discussed. The numerical results are obtained using the variational uniform matrix-product state (VUMPS) formalism for infinite systems, as well as the density-matrix renormalization group (DMRG) algorithm for finite systems.
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Affiliation(s)
- Yuchi He
- Institut für Theorie der Statistischen Physik, RWTH Aachen University and JARA-Fundamentals of Future Information Technology, 52056 Aachen, Germany
- Rudolf Peierls Centre for Theoretical Physics, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Dante M Kennes
- Institut für Theorie der Statistischen Physik, RWTH Aachen University and JARA-Fundamentals of Future Information Technology, 52056 Aachen, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761 Hamburg, Germany
| | - Christoph Karrasch
- Technische Universität Braunschweig, Institut für Mathematische Physik, Mendelssohnstraße 3, 38106 Braunschweig, Germany
| | - Roman Rausch
- Technische Universität Braunschweig, Institut für Mathematische Physik, Mendelssohnstraße 3, 38106 Braunschweig, Germany
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2
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Das S, Dey D, Raghunathan R, Soos ZG, Kumar M, Ramasesha S. Quantum phase transitions in skewed ladder systems. Phys Chem Chem Phys 2023; 26:36-46. [PMID: 38086628 DOI: 10.1039/d3cp04179d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
In this brief review, we introduce a new spin ladder system called skewed spin ladders and discuss the exotic quantum phases of this system. The spin ladders studied are the 5/7, 3/4 and 3/5 systems corresponding to alternately fused 5 and 7 membered rings; 3 and 4 membered rings; and 3 and 5 membered rings. These ladders show completely different behaviour as the Hamiltonian model parameter is changed. When the Hamiltonian parameter is increased the 5/7 ladder switches from an initial singlet ground state to progressively higher spin ground state and then to a reentrant singlet state before finally settling to the highest spin ground state whose spin equals the number of unit cells in the system. The 3/4 ladder goes from a singlet ground state to a high spin ground state with each unit cell contributing spin 1 to the state, as the model parameter is increased. The 3/5 ladder shows a singlet ground state for small parameters and high spin ground state for intermediate values of the parameter and for still higher parameters, a reentrant singlet ground state. They can also show interesting magnetization plateaus as illustrated by studies on a specific spin ladder.
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Affiliation(s)
- Sambunath Das
- Institute of Physics (FZU), Czech Academy of Sciences, Na Slovance 1999/2, 182 00 Prague, Czech Republic
| | - Dayasindhu Dey
- UGC-DAE Consortium for Scientific Research, Indore-452001, Madhya Pradesh, India
| | - Rajamani Raghunathan
- UGC-DAE Consortium for Scientific Research, Indore-452001, Madhya Pradesh, India
| | - Zoltan G Soos
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Manoranjan Kumar
- S. N. Bose National Centre for Basic Sciences, Block - JD, Sector - III, Salt Lake, Kolkata-700106, India.
| | - S Ramasesha
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, India.
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3
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Xiang ZC, Huang K, Zhang YR, Liu T, Shi YH, Deng CL, Liu T, Li H, Liang GH, Mei ZY, Yu H, Xue G, Tian Y, Song X, Liu ZB, Xu K, Zheng D, Nori F, Fan H. Simulating Chern insulators on a superconducting quantum processor. Nat Commun 2023; 14:5433. [PMID: 37669968 PMCID: PMC10480218 DOI: 10.1038/s41467-023-41230-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 08/23/2023] [Indexed: 09/07/2023] Open
Abstract
The quantum Hall effect, fundamental in modern condensed matter physics, continuously inspires new theories and predicts emergent phases of matter. Here we experimentally demonstrate three types of Chern insulators with synthetic dimensions on a programable 30-qubit-ladder superconducting processor. We directly measure the band structures of the 2D Chern insulator along synthetic dimensions with various configurations of Aubry-André-Harper chains and observe dynamical localisation of edge excitations. With these two signatures of topology, our experiments implement the bulk-edge correspondence in the synthetic 2D Chern insulator. Moreover, we simulate two different bilayer Chern insulators on the ladder-type superconducting processor. With the same and opposite periodically modulated on-site potentials for two coupled chains, we simulate topologically nontrivial edge states with zero Hall conductivity and a Chern insulator with higher Chern numbers, respectively. Our work shows the potential of using superconducting qubits for investigating different intriguing topological phases of quantum matter.
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Affiliation(s)
- Zhong-Cheng Xiang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Kaixuan Huang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
- Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, Teda Applied Physics Institute and School of Physics, Nankai University, Tianjin, 300457, China
| | - Yu-Ran Zhang
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, 510640, China
- Theoretical Quantum Physics Laboratory, Cluster for Pioneering Research, RIKEN, Wako-shi, Saitama, 351-0198, Japan
- Center for Quantum Computing, RIKEN, Wako-shi, Saitama, 351-0198, Japan
| | - Tao Liu
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, 510640, China
| | - Yun-Hao Shi
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Cheng-Lin Deng
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Tong Liu
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Hao Li
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Gui-Han Liang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zheng-Yang Mei
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Haifeng Yu
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Guangming Xue
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Ye Tian
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiaohui Song
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhi-Bo Liu
- Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, Teda Applied Physics Institute and School of Physics, Nankai University, Tianjin, 300457, China
| | - Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- CAS Centre for Excellence in Topological Quantum Computation, UCAS, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, China.
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- CAS Centre for Excellence in Topological Quantum Computation, UCAS, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, 523808, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, Cluster for Pioneering Research, RIKEN, Wako-shi, Saitama, 351-0198, Japan.
- Center for Quantum Computing, RIKEN, Wako-shi, Saitama, 351-0198, Japan.
- Physics Department, University of Michigan, Ann Arbor, MI, 48109-1040, USA.
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- CAS Centre for Excellence in Topological Quantum Computation, UCAS, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, China.
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4
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Tseng Y, Paris E, Schmidt KP, Zhang W, Asmara TC, Bag R, Strocov VN, Singh S, Schlappa J, Rønnow HM, Schmitt T. Momentum-resolved spin-conserving two-triplon bound state and continuum in a cuprate ladder. COMMUNICATIONS PHYSICS 2023; 6:138. [PMID: 38665396 PMCID: PMC11041747 DOI: 10.1038/s42005-023-01250-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 05/23/2023] [Indexed: 04/28/2024]
Abstract
Studying multi-particle elementary excitations has provided unique access to understand collective many-body phenomena in correlated electronic materials, paving the way towards constructing microscopic models. In this work, we perform O K-edge resonant inelastic X-ray scattering (RIXS) on the quasi-one-dimensional cuprate Sr 14 Cu 24 O 41 with weakly-doped spin ladders. The RIXS signal is dominated by a dispersing sharp mode ~ 270 meV on top of a damped incoherent component ~ 400-500 meV. Comparing with model calculations using the perturbative continuous unitary transformations method, the two components resemble the spin-conserving ΔS = 0 two-triplon bound state and continuum excitations in the spin ladders. Such multi-spin response with long-lived ΔS = 0 excitons is central to several exotic magnetic properties featuring Majorana fermions, yet remains unexplored given the generally weak cross-section with other experimental techniques. By investigating a simple spin-ladder model system, our study provides valuable insight into low-dimensional quantum magnetism.
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Affiliation(s)
- Yi Tseng
- Photon Science Division, Paul Scherrer Institut, Forschungstrasse 111, CH-5232 Villigen PSI, Switzerland
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Present Address: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Eugenio Paris
- Photon Science Division, Paul Scherrer Institut, Forschungstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Kai P. Schmidt
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstraße 7, D-91058 Erlangen, Germany
| | - Wenliang Zhang
- Photon Science Division, Paul Scherrer Institut, Forschungstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Teguh Citra Asmara
- Photon Science Division, Paul Scherrer Institut, Forschungstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Rabindranath Bag
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, Maharashtra 411008 India
- Present Address: Department of Physics, Duke University, Durham, NC 27708 USA
| | - Vladimir N. Strocov
- Photon Science Division, Paul Scherrer Institut, Forschungstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Surjeet Singh
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, Maharashtra 411008 India
| | - Justine Schlappa
- Photon Science Division, Paul Scherrer Institut, Forschungstrasse 111, CH-5232 Villigen PSI, Switzerland
- European X-Ray Free-Electron Laser Facility GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Henrik M. Rønnow
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Thorsten Schmitt
- Photon Science Division, Paul Scherrer Institut, Forschungstrasse 111, CH-5232 Villigen PSI, Switzerland
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5
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Adamus P, Xu B, Marsik P, Dubroka A, Barabasová P, Růžičková H, Puphal P, Pomjakushina E, Tallon JL, Mathis YL, Munzar D, Bernhard C. Analogies of phonon anomalies and electronic gap features in the infrared response of Sr14-xCa xCu 24O 41and underdoped YBa 2Cu 3O6+x. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 86:044502. [PMID: 36821858 DOI: 10.1088/1361-6633/acbe4f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
We present an experimental and theoretical study which compares the phonon anomalies and the electronic gap features in the infrared response of the weakly coupled two-leg-ladders in Sr14-xCaxCu24O41(SCCO) with those of the underdoped high-Tcsuperconductor YBa2Cu3O6+x(YBCO) and thereby reveals some surprising analogies. Specifically, we present a phenomenological model that describes the anomalous doping- and temperature-dependence of some of the phonon features in thea-axis response (field along the rungs of the ladders) of SCCO. It assumes that the phonons are coupled to charge oscillations within the ladders. Their changes with decreasing temperature reveal the formation of a crystal (density wave) of hole pairs that are oriented along the rungs. We also discuss the analogy to a similar model that was previously used to explain the phonon anomalies and an electronic plasma mode in thec-axis response (field perpendicular to the CuO2planes) of YBCO. We further confirm that an insulator-like pseudogap develops in thea-axis conductivity of SCCO which closely resembles that in thec-axis conductivity of YBCO. Most surprisingly, we find that thec-axis conductivity (field along the legs of the ladders) of SCCO is strikingly similar to the in-plane one (field parallel to the CuO2planes) of YBCO. Notably, in both cases a dip feature develops in the normal state spectra that is connected with a spectral weight shift toward low frequencies and can thus be associated with precursor superconducting pairing correlations that are lacking macroscopic phase coherence. This SCCO-YBCO analogy indicates that collective degrees of freedom contribute to the low-energy response of underdoped highTccuprates and it even suggests that the charges in the CuO2planes tend to segregate forming quasi-one-dimensional structures similar to the two-leg ladders, as predicted for the stripe-scenario or certain intertwinned states.
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Affiliation(s)
- Petr Adamus
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | - Bing Xu
- University of Fribourg, Department of Physics, Chemin du Musée 3, CH-1700 Fribourg, Switzerland
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Premysl Marsik
- University of Fribourg, Department of Physics, Chemin du Musée 3, CH-1700 Fribourg, Switzerland
| | - Adam Dubroka
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | - Paulína Barabasová
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | - Hana Růžičková
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | - Pascal Puphal
- Laboratory for Multiscale Materials Experiments, PSI, 5232 Villigen, Switzerland
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | | | - Jeffery L Tallon
- Victoria University of Wellington, Robinson Research Institute, POB 33436, Lower Hutt 5046, New Zealand
| | - Yves-Laurent Mathis
- Karlsruhe Institute of Technology, Institute for Beam Physics and Technology, Hermann-von-Helmhotz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Dominik Munzar
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | - Christian Bernhard
- University of Fribourg, Department of Physics, Chemin du Musée 3, CH-1700 Fribourg, Switzerland
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6
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Chatterjee M, Maiti D, Kumar M. Quantum Phase Diagram of a Frustrated Spin-1/2 Ferro-Antiferromagnetic Normal Ladder. Chemphyschem 2023; 24:e202200538. [PMID: 36315358 DOI: 10.1002/cphc.202200538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 10/31/2022] [Accepted: 10/31/2022] [Indexed: 12/14/2022]
Abstract
In this work, we consider a frustrated two-leg spin-1/2 ladder composed of Heisenberg ferromagnetic and antiferromagnetic spin-1/2 chains, and nearest spins from different legs interact via Heisenberg type rung exchange interactions that can be either ferromagnetic or antiferromagnetic in nature. The competing exchange interactions in the system lead to five different quantum phases like ferromagnetic, non-collinear ferrimagnetic (NCF), m - 1 / 4 ${m - 1/4}$ , antiferromagnetic and dimer phases. The quantum phase diagram is constructed for the Heisenberg spin-1/2 model and the phases are characterized using the correlation functions which are calculated by the density matrix renormalization group method. We also analyze the stability of m - 1 / 4 ${m - 1/4}$ phase and calculate the pitch angle θ ${\left( \theta \right)}$ in the NCF phase.
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Affiliation(s)
- Monalisa Chatterjee
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata, 700106, India
| | - Debasmita Maiti
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata, 700106, India.,Department of Physics, National Tsing Hua University, Hsinchu, 300044, Taiwan
| | - Manoranjan Kumar
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata, 700106, India
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7
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Li Manni G, Kats D, Liebermann N. Resolution of Electronic States in Heisenberg Cluster Models within the Unitary Group Approach. J Chem Theory Comput 2023; 19:1218-1230. [PMID: 36735906 PMCID: PMC9979614 DOI: 10.1021/acs.jctc.2c01132] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this work ground and excited electronic states of Heisenberg cluster models, in the form of configuration interaction many-body wave functions, are characterized within the spin-adapted Graphical Unitary Group Approach framework, and relying on a novel combined unitary and symmetric group approach. Finite-size cluster models of well-defined point-group symmetry and of general local-spin Slocal>12 are presented, including J1-J2 triangular and tetrahedral clusters, which are often used to describe magnetic interactions in biological and biomimetic polynuclear transition metal clusters with unique catalytic activity, such as nitrogen fixation and photosynthesis. We show that a unique block-diagonal structure of the underlying Hamiltonian matrix in the spin-adapted basis emerges when an optimal lattice site ordering is chosen that reflects the internal symmetries of the model investigated. The block-diagonal structure is bound to the commutation relations between cumulative spin operators and the Hamiltonian operator, that in turn depend on the geometry of the cluster investigated. The many-body basis transformation, in the form of the orbital/site reordering, exposes such commutation relations. These commutation relations represent a rigorous and formal demonstration of the block-diagonal structure in Hamiltonian matrices and the compression of the corresponding spin-adapted many-body wave functions. As a direct consequence of the block-diagonal structure of the Hamiltonian matrix, it is possible to selectively optimize electronic excited states without the overhead of calculating the lower-energy states by simply relying on the initial ansatz for the targeted wave function. Additionally, more compact many-body wave functions are obtained. In extreme cases, electronic states are precisely described by a single configuration state function, despite the curse of dimensionality of the corresponding Hilbert space. These findings are crucial in the electronic structure theory framework, for they offer a conceptual route toward wave functions of reduced multireference character, that can be optimized more easily by approximated eigensolvers and are of more facile physical interpretation. They open the way to study larger ab initio and model Hamiltonians of increasingly larger number of correlated electrons, while keeping the computational costs at their lowest. In particular, these elements will expand the potential of electronic structure methods in understanding magnetic interactions in exchange-coupled polynuclear transition metal clusters.
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Alshalawi DR, Alonso JM, Landa-Cánovas AR, de la Presa P. Coexistence of Two Spin Frustration Pathways in the Quantum Spin Liquid Ca 10Cr 7O 28. Inorg Chem 2022; 61:16228-16238. [PMID: 36191153 PMCID: PMC9580002 DOI: 10.1021/acs.inorgchem.2c01831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Kagome antiferromagnetic
lattices are of high interest
because
the geometric frustration is expected to give rise to highly degenerated
ground states that may host exotic properties such as quantum spin
liquid (QSL). Ca10Cr7O28 has been
reported to display all the features expected for a QSL. At present,
most of the literature reports on samples synthesized with starting
materials ratio CaO/Cr2O3 3:1, which leads to
a material with small amounts of CaCrO4 and CaO as secondary
phases; this impurity excess affects not only the magnetic properties
but also the structural ones. In this work, samples with starting
material ratios CaO/Cr2O3 3:1, 2.9:1, 2.85:1,
and 2.8:1 have been synthesized and studied by X-ray diffraction with
Rietveld refinements, selected area electron diffraction measurements,
high-resolution transmission electron microscopy (HRTEM), low-temperature
magnetometry, and magnetic calorimetry. This result shows that a highly
pure Ca10Cr7O28 phase is obtained
for a CaO/Cr2O3 ratio of 2.85:1 instead of the
3:1 usually reported; the incorrect stoichiometric ratio leads to
a larger distortion of the corner-sharing triangular arrangement of
magnetic ions Cr+5 with S = 1/2 in the
Kagome lattice. In addition, our study reveals that there exists another
frustration pathway which is an asymmetric zigzag spin ladder along
the directions [211], [12–1], and [1–1–1], in
which the Cr–Cr distances are shorter than in the Kagome layers. This work represents the endeavor to
ensure the correct
stoichiometric composition of the quantum spin liquid material Ca10Cr7O28. The synthesis and characterization
addressed several nonstoichiometric samples, including impurities’
influence on the crystal structure and properties of Kagome and zigzag
magnetic interaction. The characterization aspects of the compound
are based on the X-ray diffraction data and Rietveld refinement. Further
characterization could help us understand the nature of quantum material
and aid in the additional development of quantum theories and technology.
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Affiliation(s)
- Dhoha R Alshalawi
- Institute of Applied Magnetism, UCM-ADFI-CSIC, A6 22,500 km, Las Rozas28230, Spain.,Department of Materials Physics, Complutense University of Madrid, Madrid28040, Spain
| | - José M Alonso
- Institute of Applied Magnetism, UCM-ADFI-CSIC, A6 22,500 km, Las Rozas28230, Spain.,Institute of Material Science of Madrid, CSIC, Madrid28049, Spain
| | | | - Patricia de la Presa
- Institute of Applied Magnetism, UCM-ADFI-CSIC, A6 22,500 km, Las Rozas28230, Spain.,Department of Materials Physics, Complutense University of Madrid, Madrid28040, Spain
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9
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Hagymási I, Mohd Isa MS, Tajkov Z, Márity K, Oroszlány L, Koltai J, Alassaf A, Kun P, Kandrai K, Pálinkás A, Vancsó P, Tapasztó L, Nemes-Incze P. Observation of competing, correlated ground states in the flat band of rhombohedral graphite. SCIENCE ADVANCES 2022; 8:eabo6879. [PMID: 36054359 PMCID: PMC10848960 DOI: 10.1126/sciadv.abo6879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
In crystalline solids, the interactions of charge and spin can result in a variety of emergent quantum ground states, especially in partially filled, topological flat bands such as Landau levels or in "magic angle" graphene layers. Much less explored is rhombohedral graphite (RG), perhaps the simplest and structurally most perfect condensed matter system to host a flat band protected by symmetry. By scanning tunneling microscopy, we map the flat band charge density of 8, 10, 14, and 17 layers and identify a domain structure emerging from a competition between a sublattice antiferromagnetic insulator and a gapless correlated paramagnet. Our density matrix renormalization group calculations explain the observed features and demonstrate that the correlations are fundamentally different from graphene-based magnetism identified until now, forming the ground state of a quantum magnet. Our work establishes RG as a platform to study many-body interactions beyond the mean-field approach, where quantum fluctuations and entanglement dominate.
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Affiliation(s)
- Imre Hagymási
- Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany
- Wigner Research Centre for Physics, 1121 Budapest, Hungary
- Dahlem Center for Complex Quantum Systems and Institut für Theoretische Physik, Freie Universität Berlin, 14195 Berlin, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Mohammad Syahid Mohd Isa
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
| | - Zoltán Tajkov
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
- Department of Biological Physics, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
| | - Krisztián Márity
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
| | - László Oroszlány
- Department of Physics of Complex Systems, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
- Budapest University of Technology and Economics, 1111 Budapest, Hungary
| | - János Koltai
- Department of Biological Physics, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
| | - Assem Alassaf
- Department of Physics of Complex Systems, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
| | - Péter Kun
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
| | - Konrád Kandrai
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
| | - András Pálinkás
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
| | - Péter Vancsó
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
| | - Levente Tapasztó
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
| | - Péter Nemes-Incze
- Centre for Energy Research, Institute of Technical Physics and Materials Science, 1121 Budapest, Hungary
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10
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Monroe JC, Carvajal MA, Landee CP, Deumal M, Turnbull MM, Wikaira JL, Dawe LN. Approaching the isotropic spin-ladder regime: structure and magnetism of all-pyrazine-bridged copper(II)-based antiferromagnetic ladders. Dalton Trans 2022; 51:4653-4667. [PMID: 35212329 DOI: 10.1039/d1dt04219j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crystal structure and magnetic properties of two all-pyrazine-bridged antiferromagnetic spin ladders are reported. The complexes, catena-(bis(3-X-4-pyridone)(μ-pyrazine)copper(II)(-μ-pyrazine)diperchlorate ([Cu(pz)1.5(L)2](ClO4)2 where L = 3-X-4-pyridone and X = Br (1) or Cl (2)), contain copper(II)-based ladders in which both the rung and rail bridges are pyrazine molecules bonded through the x2-y2 orbital of the copper(II) ions. This structural scaffold is proposed to approach the isotropic spin-ladder regime. 1 and 2 crystallize in the monoclinic space group P21/c. Due to the bulk of the 3-X-4-HOpy ligands, the ladders are well isolated in the a-direction (1, 15.6 Å; 2, 15.5 Å). The ladders, which run in the b-direction, are stacked in the c-direction with the separation (1, 7.87 Å; 2, 7.82 Å) between copper(II) ions caused by the bulk of a semi-coordinate perchlorate ion coordinated in the axial position. Computational evaluation of magnetic JAB couplings between Cu-moieties of 2 supports the experimentally proposed magnetic topology and agrees with an isolated isotropic spin-ladder (Jrail = -4.04 cm-1 (-5.77 K) and Jrung = -3.89 cm-1 (-5.56 K)). These complexes introduce a convenient scaffold for synthesizing isotropic spin-ladders with modest superexchange interactions, the strength of which may be tuned by variations in L. The magnetic susceptibility down to 1.8 K, for both compounds, is well described by the strong-rung ladder model giving nearly isotropic exchange with Jrung ≈ Jrail ≈ -5.5 K (1) and -5.9 K (2) using the Hamiltonian. Theoretical simulations of the magnetic response of 2 using the isotropic ladder model are in excellent agreement with experiment. The measured magnetization to 5 T indicates a quantum-dominated magnetic spectrum. Again, calculated lower and saturation (4.3 and 24 T, respectively) critical fields for 2 are consistent with experimental measurements, and magnetization data at very low temperatures indeed suggest the presence of quantum effects. Further, the computational study of short- and long-range spin ordering indicates that a 2D-to-3D crossover might be feasible at lower temperatures. Analysis of the Boltzmann population corroborates the presence of accessible triplet states above the singlet ground state enabling the aforementioned 2D-to-3D crossover.
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Affiliation(s)
- Jeffrey C Monroe
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, MA 01610, USA.
| | - M Angels Carvajal
- Dept. Ciència de Materials i Química Física, & IQCTUB, Universitat de Barcelona, Martí i Franquès 1, Barcelona, E-08028, Spain
| | - Christopher P Landee
- Department of Physics, Clark University 950 Main Street, Worcester, MA 01610, USA
| | - Mercè Deumal
- Dept. Ciència de Materials i Química Física, & IQCTUB, Universitat de Barcelona, Martí i Franquès 1, Barcelona, E-08028, Spain
| | - Mark M Turnbull
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, MA 01610, USA.
| | - Jan L Wikaira
- Department of Chemistry, University of Canterbury, 20 Kirkwood Ave, Upper Riccarton, Christchurch 8041, New Zealand
| | - Louise N Dawe
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada
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11
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Li L, Ding F, Zheng H, Pan B. Synthesis, Structure and Properties of a New Strong‐Rung Spin Ladder Compound Cu(2‐Ethylpyrazine)Br
2. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202100994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ling‐Li Li
- School of Physics and Optoelectronic Engineering Ludong University Yantai Shandong 264025 China
| | - Fei Ding
- School of Physics and Optoelectronic Engineering Ludong University Yantai Shandong 264025 China
| | - Hui Zheng
- School of Chemistry and Materials Science Ludong University Yantai Shandong 264025 China
| | - Bing‐Ying Pan
- School of Physics and Optoelectronic Engineering Ludong University Yantai Shandong 264025 China
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12
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Topological Doping and Superconductivity in Cuprates: An Experimental Perspective. Symmetry (Basel) 2021. [DOI: 10.3390/sym13122365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Hole doping into a correlated antiferromagnet leads to topological stripe correlations, involving charge stripes that separate antiferromagnetic spin stripes of opposite phases. The topological spin stripe order causes the spin degrees of freedom within the charge stripes to feel a geometric frustration with their environment. In the case of cuprates, where the charge stripes have the character of a hole-doped two-leg spin ladder, with corresponding pairing correlations, anti-phase Josephson coupling across the spin stripes can lead to a pair-density-wave order in which the broken translation symmetry of the superconducting wave function is accommodated by pairs with finite momentum. This scenario is now experimentally verified by recently reported measurements on La2−xBaxCuO4 with x=1/8. While pair-density-wave order is not common as a cuprate ground state, it provides a basis for understanding the uniform d-wave order that is more typical in superconducting cuprates.
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13
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Sous J, Gadjieva NA, Nuckolls C, Reichman DR, Millis AJ. Strongly Correlated Ladders in K-Doped p-Terphenyl Crystals. NANO LETTERS 2021; 21:9573-9579. [PMID: 34761676 DOI: 10.1021/acs.nanolett.1c03236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Potassium-doped terphenyl has recently attracted attention as a potential host for high-transition-temperature superconductivity. Here, we elucidate the many-body electronic structure of recently synthesized potassium-doped terphenyl crystals. We show that this system may be understood as a set of weakly coupled one-dimensional ladders. Depending on the strength of the interladder coupling, the system may exhibit insulating spin-gapped valence-bond solid or antiferromagnetic phases, both of which upon hole doping may give rise to superconductivity. This terphenyl-based ladder material serves as a new platform for investigating the fate of ladder phases in the presence of three-dimensional coupling as well as for novel superconductivity.
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Affiliation(s)
- John Sous
- Department of Physics, Columbia University, New York, New York 10027, United States
| | - Natalia A Gadjieva
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Colin Nuckolls
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - David R Reichman
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Andrew J Millis
- Department of Physics, Columbia University, New York, New York 10027, United States
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, United States
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14
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Li HB, Kobayashi S, Zhong C, Namba M, Cao Y, Kato D, Kotani Y, Lin Q, Wu M, Wang WH, Kobayashi M, Fujita K, Tassel C, Terashima T, Kuwabara A, Kobayashi Y, Takatsu H, Kageyama H. Dehydration of Electrochemically Protonated Oxide: SrCoO 2 with Square Spin Tubes. J Am Chem Soc 2021; 143:17517-17525. [PMID: 34647722 DOI: 10.1021/jacs.1c07043] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Controlling oxygen deficiencies is essential for the development of novel chemical and physical properties such as high-Tc superconductivity and low-dimensional magnetic phenomena. Among reduction methods, topochemical reactions using metal hydrides (e.g., CaH2) are known as the most powerful method to obtain highly reduced oxides including Nd0.8Sr0.2NiO2 superconductor, though there are some limitations such as competition with oxyhydrides. Here we demonstrate that electrochemical protonation combined with thermal dehydration can yield highly reduced oxides: SrCoO2.5 thin films are converted to SrCoO2 by dehydration of HSrCoO2.5 at 350 °C. SrCoO2 forms square (or four-legged) spin tubes composed of tetrahedra, in contrast to the conventional infinite-layer structure. Detailed analyses suggest the importance of the destabilization of the SrCoO2.5 precursor by electrochemical protonation that can greatly alter reaction energy landscape and its gradual dehydration (H1-xSrCoO2.5-x/2) for the SrCoO2 formation. Given the applicability of electrochemical protonation to a variety of transition metal oxides, this simple process widens possibilities to explore novel functional oxides.
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Affiliation(s)
- Hao-Bo Li
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Shunsuke Kobayashi
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
| | - Chengchao Zhong
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Morito Namba
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Yu Cao
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Daichi Kato
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Yoshinori Kotani
- Japan Synchrotron Radiation Research Institute, Sayo-cho, Hyogo 679-5198, Japan
| | - Qianmei Lin
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Maokun Wu
- Department of Electronic Science and Engineering and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University, Tianjin 300071, China
| | - Wei-Hua Wang
- Department of Electronic Science and Engineering and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University, Tianjin 300071, China
| | - Masaki Kobayashi
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Koji Fujita
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Cédric Tassel
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Takahito Terashima
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Akihide Kuwabara
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
| | - Yoji Kobayashi
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Hiroshi Takatsu
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Hiroshi Kageyama
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
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15
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Arauzo A, Bartolomé E, Luzón J, Alonso PJ, Vlad A, Cazacu M, Zaltariov MF, Shova S, Bartolomé J, Turta C. Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H 2O} n MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs. Molecules 2021; 26:5626. [PMID: 34577095 PMCID: PMC8466197 DOI: 10.3390/molecules26185626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/03/2021] [Accepted: 09/10/2021] [Indexed: 11/17/2022] Open
Abstract
We present the magnetic properties of the metal-organic framework {[CoCxAPy]·2.15 H2O}n (Cx = bis(carboxypropyl)tetramethyldisiloxane; APy = 4,4`-azopyridine) (1) that builds up from the stacking of 2D coordination polymers. The 2D-coordination polymer in the bc plane is formed by the adjacent bonding of [CoCxAPy] 1D two-leg ladders with Co dimer rungs, running parallel to the c-axis. The crystal packing of 2D layers shows the presence of infinite channels running along the c crystallographic axis, which accommodate the disordered solvate molecules. The Co(II) is six-coordinated in a distorted octahedral geometry, where the equatorial plane is occupied by four carboxylate oxygen atoms. Two nitrogen atoms from APy ligands are coordinated in apical positions. The single-ion magnetic anisotropy has been determined by low temperature EPR and magnetization measurements on an isostructural compound {[Zn0.8Co0.2CxAPy]·1.5 CH3OH}n (2). The results show that the Co(II) ion has orthorhombic anisotropy with the hard-axis direction in the C2V main axis, lying the easy axis in the distorted octahedron equatorial plane, as predicted by the ab initio calculations of the g-tensor. Magnetic and heat capacity properties at very low temperatures are rationalized within a S* = 1/2 magnetic dimer model with anisotropic antiferromagnetic interaction. The magnetic dimer exhibits slow relaxation of the magnetization (SMM) below 6 K in applied field, with a tlf ≈ 2 s direct process at low frequencies, and an Orbach process at higher frequencies with U/kB = 6.7 ± 0.5 K. This compound represents a singular SMM MOF built-up of Co-dimers with an anisotropic exchange interaction.
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Affiliation(s)
- Ana Arauzo
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain; (J.L.); (P.J.A.); (J.B.)
| | - Elena Bartolomé
- Department of Mechanical Engineering, Escola Universitària Salesiana de Sarrià (EUSS), Passeig de Sant Joan Bosco, 74, 08017 Barcelona, Spain;
| | - Javier Luzón
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain; (J.L.); (P.J.A.); (J.B.)
- Centro Universitario de la Defensa, Ctra. de Huesca s/n, 50090 Zaragoza, Spain
| | - Pablo J. Alonso
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain; (J.L.); (P.J.A.); (J.B.)
| | - Angelica Vlad
- Department of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania; (A.V.); (M.C.); (M.F.Z.); (S.S.)
| | - Maria Cazacu
- Department of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania; (A.V.); (M.C.); (M.F.Z.); (S.S.)
| | - Mirela F. Zaltariov
- Department of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania; (A.V.); (M.C.); (M.F.Z.); (S.S.)
| | - Sergiu Shova
- Department of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania; (A.V.); (M.C.); (M.F.Z.); (S.S.)
| | - Juan Bartolomé
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain; (J.L.); (P.J.A.); (J.B.)
| | - Constantin Turta
- Department of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania; (A.V.); (M.C.); (M.F.Z.); (S.S.)
- Institute of Chemistry, Academy of Sciences of Moldova, Academiei 3, MD-2028 Chisinau, Moldova
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16
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Saniur Rahaman S, Sahoo S, Kumar M. Quantum phases and thermodynamics of a frustrated spin-1/2 ladder with alternate Ising-Heisenberg rung interactions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:265801. [PMID: 33857937 DOI: 10.1088/1361-648x/abf882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
We study a frustrated two-leg spin ladder with alternate isotropic Heisenberg and Ising rung exchange interactions, whereas, interactions along legs and diagonals are Ising-type. All the interactions in the ladder are anti-ferromagnetic in nature and induce frustration in the system. This model shows four interesting quantum phases: (i) stripe rung ferromagnetic (SRFM), (ii) stripe rung ferromagnetic with edge singlet (SRFM-E), (iii) anisotropic antiferromagnetic (AAFM), and (iv) stripe leg ferromagnetic (SLFM) phase. We construct a quantum phase diagram for this model and show that in stripe rung ferromagnet (SRFM), the same type of sublattice spins (either isotropicS-type or discrete anisotropicσ-type spins) are aligned in the same direction. Whereas, in anisotropic antiferromagnetic phase, bothSandσ-type of spins are anti-ferromagnetically aligned with each other, two nearestSspins along the rung form an anisotropic singlet bond whereas two nearestσspins form an Ising bond. In large Heisenberg rung exchange interaction limit, spins on each leg are ferromagnetically aligned, but spins on different legs are anti-ferromagnetically aligned. The thermodynamic quantities like specific heatCv(T), magnetic susceptibilityχ(T) and thermal entropyS(T) are also calculated using the transfer matrix method for various phases. The magnetic gap in the SRFM and the SLFM can be noticed fromχ(T) andCv(T) curves.
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Affiliation(s)
- Sk Saniur Rahaman
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
| | - Shaon Sahoo
- Department of Physics, Indian Institute of Technology, Tirupati, India
| | - Manoranjan Kumar
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
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17
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Saha-Dasgupta T. The Fascinating World of Low-Dimensional Quantum Spin Systems: Ab Initio Modeling. Molecules 2021; 26:molecules26061522. [PMID: 33802160 PMCID: PMC7998400 DOI: 10.3390/molecules26061522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/03/2021] [Accepted: 03/03/2021] [Indexed: 11/16/2022] Open
Abstract
In recent times, ab initio density functional theory has emerged as a powerful tool for making the connection between models and materials. Insulating transition metal oxides with a small spin forms a fascinating class of strongly correlated systems that exhibit spin-gap states, spin–charge separation, quantum criticality, superconductivity, etc. The coupling between spin, charge, and orbital degrees of freedom makes the chemical insights equally important to the strong correlation effects. In this review, we establish the usefulness of ab initio tools within the framework of the N-th order muffin orbital (NMTO)-downfolding technique in the identification of a spin model of insulating oxides with small spins. The applicability of the method has been demonstrated by drawing on examples from a large number of cases from the cuprate, vanadate, and nickelate families. The method was found to be efficient in terms of the characterization of underlying spin models that account for the measured magnetic data and provide predictions for future experiments.
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Affiliation(s)
- Tanusri Saha-Dasgupta
- S.N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
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18
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Mortemousque PA, Chanrion E, Jadot B, Flentje H, Ludwig A, Wieck AD, Urdampilleta M, Bäuerle C, Meunier T. Coherent control of individual electron spins in a two-dimensional quantum dot array. NATURE NANOTECHNOLOGY 2021; 16:296-301. [PMID: 33349684 DOI: 10.1038/s41565-020-00816-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/03/2020] [Indexed: 06/12/2023]
Abstract
The coherent manipulation of individual quantum objects organized in arrays is a prerequisite to any scalable quantum information platform. The cumulated efforts to control electron spins in quantum dot arrays have permitted the recent realization of quantum simulators and multielectron spin-coherent manipulations. Although a natural path to resolve complex quantum-matter problems and to process quantum information, two-dimensional (2D) scaling with a high connectivity of such implementations remains undemonstrated. Here we demonstrate the 2D coherent control of individual electron spins in a 3 × 3 array of tunnel-coupled quantum dots. We focus on several key quantum functionalities: charge-deterministic loading and displacement, local spin readout and local coherent exchange manipulation between two electron spins trapped in adjacent dots. This work lays some of the foundations to exploit a 2D array of electron spins for quantum simulation and information processing.
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Affiliation(s)
- Pierre-André Mortemousque
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France.
- Université Grenoble Alpes, CEA, Leti, Grenoble, France.
| | - Emmanuel Chanrion
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Baptiste Jadot
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Hanno Flentje
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Matias Urdampilleta
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Christopher Bäuerle
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Tristan Meunier
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France.
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19
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Kong QR, Li D, Liu XL, Zhao HX, Ren YP, Long LS, Zheng LS. Magnetodielectric Response in a Layered Mixed-Valence Ferrimagnetic Molecular Compound. Inorg Chem 2021; 60:3565-3571. [PMID: 33619966 DOI: 10.1021/acs.inorgchem.0c02549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The magnetodielectric effect is closely related to multiferroic or magnetoelectric coupling; thus, it can be used to predict magnetoelectric coupling, especially in compounds with special magnetic properties. The magnetodielectric response can often be used to predict many interesting and meaningful physical coupling mechanisms. Therefore, fabricating magnetodielectric materials is an effective step toward the development of magnetoelectric materials. Herein, we synthesize the mixed-valence layered ferrimagnetic molecular compound (C6N2H14)FeIII2FeIIF8(HCOO)2 (1) and demonstrate that it exhibits both slow magnetic relaxation behavior and long-range magnetic order. This long-range order occurs because of the coexistence and competition between two typical magnetic interactions, namely, an FeIII-F-FeII superexchange and a long-distance superexchange FeII-O-C-O-FeIII-F-FeIII path in the interlayer and interchain spin frustration. Notably, this compound also demonstrates two abnormal dielectric relaxation processes: the first process is dominated by dynamic guest cations, while the other process is related to the increasing magnetic correlation. Over a wide temperature range below 170 K, the magnetodielectric effect reveals that the magnetic correlation maybe promotes electron dynamics and leads to magnetodielectric coupling. These findings pave a novel path for designing magnetodielectric molecular materials.
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Affiliation(s)
- Qing-Rong Kong
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Dong Li
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Xiao-Lin Liu
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Hai-Xia Zhao
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Yan-Ping Ren
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - La-Sheng Long
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Lan-Sun Zheng
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
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20
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Thermodynamics of General Heisenberg Spin Tetramers Composed of Coupled Quantum Dimers. MAGNETOCHEMISTRY 2021. [DOI: 10.3390/magnetochemistry7020029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Advances in quantum computing technology have been made in recent years due to the evolution of spin clusters. Recent studies have tended towards spin cluster subgeometries to understand more complex structures better. These molecular magnets provide a multitude of phenomena via exchange interactions that allow for advancements in spintronics and other magnetic system applications due to the possibility of increasing speed, data storage, memory, and stability of quantum computing systems. Using the Heisenberg spin–spin exchange Hamiltonian and exact diagonalization, we examine the evolution of quantum energy levels and thermodynamic properties for various spin configurations and exchange interactions. The XXYY quantum spin tetramer considered in this study consists of two coupled dimers with exchange interactions α1J and α1′J and a dimer–dimer exchange interaction α2J. By varying spin values and interaction strengths, we determine the exact energy eigenstates that are used to determine closed-form analytic solutions for the heat capacity and magnetic susceptibility of the system and further analyze the evolution of the properties of the system based on the parameter values chosen. Furthermore, this study shows that the Schottky anomaly shifts towards zero as the ground-state of the system approaches a quantum phase transition between spin states. Additionally, we investigate the development of phase transitions produced by the convergence of the Schottky anomaly with both variable exchange interactions and external magnetic field.
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21
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Jornet-Somoza J, Cosi F, Fumanal M, Deumal M. Disentangling the magnetic dimensionality of an alleged magnetically isolated cuprate spin-ladder CuHpCl system: a long-lasting issue. Dalton Trans 2021; 50:1754-1765. [PMID: 33459323 DOI: 10.1039/d0dt03499a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Cu2(1,4-diazacycloheptane)2Cl4 (CuHpCl) crystal is a molecular transition metal antiferromagnetic complex, whose magnetism has been a long-lasting issue. The outcome of a variety of experimental studies (on magnetic susceptibility, heat capacity, magnetization, spin gap and INS) reported many different J values depending on the fitting ladder model used. From all available experimental data, one can infer that CuHpCl is a very complex system with many competing microscopic magnetic JAB interactions that lead to its overall antiferromagnetic behavior. A first-principles bottom-up study of CuHpCl is thus necessary in order to fully disentangle its magnetism. Here we incorporate data from ab initio computations providing the magnitude of the JAB interactions to investigate the microscopic magnetic couplings in CuHpCl and, ultimately, to understand the macroscopic magnetic behavior of this crystal. Strikingly, the resulting magnetic topology can be pictured as a 3D network of interacting squared plaquette magnetic building blocks, which does not agree with the suggested ladder motif (with uniform rails) that arises from direct observation of the crystal packing. The computed magnetic susceptibility, heat capacity and magnetization data show good agreement with the experimental data. In spite of this agreement, only the calculated magnetization data are used to discriminate between the different spin regimes in CuHpCl, namely gapped singlet, partially polarized and fully polarized phases. Additional analysis of the magnetic wavefunction enables the conclusion that long-range spin correlation can be discarded as being responsible for the partially polarized phase, whose magnetic response is in fact due to the complex interplay of the magnetic moments in the 3D magnetic topology.
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Affiliation(s)
- J Jornet-Somoza
- Secció Química Física, Dept. Ciència de Materials i Química Física & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08820, Barcelona, Spain. and Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco, CFM CSIC-UPV/EHU, E-20018, San Sebastián, Spain
| | - F Cosi
- Secció Química Física, Dept. Ciència de Materials i Química Física & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08820, Barcelona, Spain.
| | - M Fumanal
- Secció Química Física, Dept. Ciència de Materials i Química Física & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08820, Barcelona, Spain.
| | - M Deumal
- Secció Química Física, Dept. Ciència de Materials i Química Física & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08820, Barcelona, Spain.
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22
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Zhang M, Cui M, Zhao Z, Huang X, He Z. A spin-1/2 gapped compound CdCu 2(SeO 3) 2Cl 2 with a ladder structure. Chem Commun (Camb) 2021; 57:6923-6926. [PMID: 34155487 DOI: 10.1039/d1cc02243a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The exploration of two-leg spin-ladder materials is a great challenge to the chemical community since it is one of the most ideal models for the study of low-dimensional magnetism and high-Tc superconductivity. Herein, we report on a successful synthesis of a new Cu2+-based two-leg ladder compound constructed by CuO4Cl2 octahedra along the [101] direction. The magnetic results exhibit a broad peak at Tmax ∼ 265 K, and suggest that CdCu2(SeO3)2Cl2 has a spin singlet ground state. The fitting of the isolated two-leg spin-ladder model shows J⊥/kB = 429 K and J‖/kB = 21 K, leading to a large spin gap of ∼409 K.
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Affiliation(s)
- Mengsi Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Meiyan Cui
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P. R. China.
| | - Zhiying Zhao
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P. R. China.
| | - Xing Huang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P. R. China.
| | - Zhangzhen He
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, P. R. China.
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23
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Mussardo G, Trombettoni A, Zhang Z. Prime Suspects in a Quantum Ladder. PHYSICAL REVIEW LETTERS 2020; 125:240603. [PMID: 33412060 DOI: 10.1103/physrevlett.125.240603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
In this Letter we set up a suggestive number theory interpretation of a quantum ladder system made of N coupled chains of spin 1/2. Using the hard-core boson representation and a leg-Hamiltonian made of a magnetic field and a hopping term, we can associate to the spins σ_{a} the prime numbers p_{a} so that the chains become quantum registers for square-free integers. The rung Hamiltonian involves permutation terms between next-neighbor chains and a coprime repulsive interaction. The system has various phases; in particular, there is one whose ground state is a coherent superposition of the first N prime numbers. We also discuss the realization of such a model in terms of an open quantum system with a dissipative Lindblad dynamics.
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Affiliation(s)
- Giuseppe Mussardo
- SISSA and INFN, Sezione di Trieste, via Beirut 2/4, I-34151 Trieste, Italy
| | - Andrea Trombettoni
- SISSA and INFN, Sezione di Trieste, via Beirut 2/4, I-34151 Trieste, Italy
- Department of Physics, University of Trieste, Strada Costiera 11, I-34151 Trieste, Italy
| | - Zhao Zhang
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
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24
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Kanbur U, Polat H, Vatansever E. Thermal properties of rung-disordered two-leg quantum spin ladders: Quantum Monte Carlo study. Phys Rev E 2020; 102:042104. [PMID: 33212615 DOI: 10.1103/physreve.102.042104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
A two-leg quenched random bond disordered antiferromagnetic spin-1/2 Heisenberg ladder system is investigated by means of stochastic series expansion quantum Monte Carlo (QMC) method. Thermal properties of the uniform and staggered susceptibilities, the structure factor, the specific heat, and the spin gap are calculated over a large number of random realizations in a wide range of disorder strength. According to our QMC simulation results, the considered system has a special temperature point at which the specific heat takes the same value regardless of the strength of the disorder. Moreover, the uniform susceptibility is shown to display the same character except for a small difference in the location of the special point. Finally, the spin gap values are found to decrease with increasing disorder parameter and the smallest gap value found in this study is well above the weak coupling limit of the clean case.
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Affiliation(s)
- Ulvi Kanbur
- The Graduate School of Natural and Applied Sciences, Dokuz Eylül University, 35390 Izmir, Turkey and Department of Physics, Karabük University, 78050 Karabük, Turkey
| | - Hamza Polat
- Department of Physics, Dokuz Eylül University, 35390 Izmir, Turkey
| | - Erol Vatansever
- Department of Physics, Dokuz Eylül University, 35390 Izmir, Turkey
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25
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Pikulski M, Shiroka T, Casola F, Reyes AP, Kuhns PL, Wang S, Ott HR, Mesot J. Two coupled chains are simpler than one: field-induced chirality in a frustrated spin ladder. Sci Rep 2020; 10:15862. [PMID: 32985519 PMCID: PMC7522251 DOI: 10.1038/s41598-020-72215-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 05/08/2020] [Indexed: 11/25/2022] Open
Abstract
Although the frustrated (zigzag) spin chain is the Drosophila of frustrated magnetism, our understanding of a pair of coupled zigzag chains (frustrated spin ladder) in a magnetic field is still lacking. We address this problem through nuclear magnetic resonance (NMR) experiments on BiCu\documentclass[12pt]{minimal}
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\begin{document}$$_6$$\end{document}6 in magnetic fields up to 45 T, revealing a field-induced spiral magnetic structure. Conjointly, we present advanced numerical calculations showing that even a moderate rung coupling dramatically simplifies the phase diagram below half-saturation magnetization by stabilizing a field-induced chiral phase. Surprisingly for a one-dimensional model, this phase and its response to Dzyaloshinskii-Moriya (DM) interactions adhere to classical expectations. While explaining the behavior at the highest accessible magnetic fields, our results imply a different origin for the solitonic phases occurring at lower fields in BiCu\documentclass[12pt]{minimal}
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\begin{document}$$_6$$\end{document}6. An exciting possibility is that the known, DM-mediated coupling between chirality and crystal lattice may give rise to a new kind of spin-Peierls instability.
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Affiliation(s)
- Marek Pikulski
- Laboratory for Solid State Physics, ETH Zürich, 8093, Zürich, Switzerland
| | - Toni Shiroka
- Laboratory for Solid State Physics, ETH Zürich, 8093, Zürich, Switzerland. .,Paul Scherrer Institut, Villigen PSI, 5232, Villigen, Switzerland.
| | - Francesco Casola
- Harvard-Smithsonian Center for Astrophysics, Harvard University, Cambridge, MA, 02138, USA
| | - Arneil P Reyes
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - Philip L Kuhns
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - Shuang Wang
- Paul Scherrer Institut, Villigen PSI, 5232, Villigen, Switzerland.,Laboratory for Quantum Magnetism, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Hans-Rudolf Ott
- Laboratory for Solid State Physics, ETH Zürich, 8093, Zürich, Switzerland.,Paul Scherrer Institut, Villigen PSI, 5232, Villigen, Switzerland
| | - Joël Mesot
- Laboratory for Solid State Physics, ETH Zürich, 8093, Zürich, Switzerland.,Paul Scherrer Institut, Villigen PSI, 5232, Villigen, Switzerland
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26
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Magnon Bose-Einstein condensation and superconductivity in a frustrated Kondo lattice. Proc Natl Acad Sci U S A 2020; 117:20462-20467. [PMID: 32788363 DOI: 10.1073/pnas.2000501117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Motivated by recent experiments on magnetically frustrated heavy fermion metals, we theoretically study the phase diagram of the Kondo lattice model with a nonmagnetic valence bond solid ground state on a ladder. A similar physical setting may be naturally occurring in [Formula: see text], [Formula: see text], and [Formula: see text] compounds. In the insulating limit, the application of a magnetic field drives a quantum phase transition to an easy-plane antiferromagnet, which is described by a Bose-Einstein condensation of magnons. Using a combination of field theoretical techniques and density matrix renormalization group calculations we demonstrate that in one dimension this transition is stable in the presence of a metallic Fermi sea, and its universality class in the local magnetic response is unaffected by the itinerant gapless fermions. Moreover, we find that fluctuations about the valence bond solid ground state can mediate an attractive interaction that drives unconventional superconducting correlations. We discuss the extensions of our findings to higher dimensions and argue that depending on the filling of conduction electrons, the magnon Bose-Einstein condensation transition can remain stable in a metal also in dimensions two and three.
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27
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Hangleiter D, Roth I, Nagaj D, Eisert J. Easing the Monte Carlo sign problem. SCIENCE ADVANCES 2020; 6:eabb8341. [PMID: 32851184 PMCID: PMC7428338 DOI: 10.1126/sciadv.abb8341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
Quantum Monte Carlo (QMC) methods are the gold standard for studying equilibrium properties of quantum many-body systems. However, in many interesting situations, QMC methods are faced with a sign problem, causing the severe limitation of an exponential increase in the runtime of the QMC algorithm. In this work, we develop a systematic, generally applicable, and practically feasible methodology for easing the sign problem by efficiently computable basis changes and use it to rigorously assess the sign problem. Our framework introduces measures of non-stoquasticity that-as we demonstrate analytically and numerically-at the same time provide a practically relevant and efficiently computable figure of merit for the severity of the sign problem. Complementing this pragmatic mindset, we prove that easing the sign problem in terms of those measures is generally an NP-complete task for nearest-neighbor Hamiltonians and simple basis choices by a reduction to the MAXCUT-problem.
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Affiliation(s)
- Dominik Hangleiter
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany
| | - Ingo Roth
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany
| | - Daniel Nagaj
- RCQI, Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jens Eisert
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany
- Helmholtz Center Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
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28
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Zhou C, Chen X, Huang Y, Pan Y, Mi J. Rational Design of (NH
4
)Cu[PO
4
] with a Spin Gapped, Distorted Honeycomb Layer. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.201901284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Chao‐Fan Zhou
- Fujian Provincial Key Laboratory of Advanced Materials (Xiamen University) Department of Materials Science and Engineering College of Materials Xiamen University 361005 Xiamen Fujian Province People's Republic of China
| | - Xiao‐Hui Chen
- Fujian Provincial Key Laboratory of Advanced Materials (Xiamen University) Department of Materials Science and Engineering College of Materials Xiamen University 361005 Xiamen Fujian Province People's Republic of China
| | - Ya‐Xi Huang
- Fujian Provincial Key Laboratory of Advanced Materials (Xiamen University) Department of Materials Science and Engineering College of Materials Xiamen University 361005 Xiamen Fujian Province People's Republic of China
| | - Yuanming Pan
- Department of Geological Sciences University of Saskatchewan SK S7N 5E2 Saskatoon Canada
| | - Jin‐Xiao Mi
- Fujian Provincial Key Laboratory of Advanced Materials (Xiamen University) Department of Materials Science and Engineering College of Materials Xiamen University 361005 Xiamen Fujian Province People's Republic of China
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29
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Nayak M, Blosser D, Zheludev A, Mila F. Magnetic-Field-Induced Bound States in Spin-1/2 Ladders. PHYSICAL REVIEW LETTERS 2020; 124:087203. [PMID: 32167323 DOI: 10.1103/physrevlett.124.087203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
Motivated by the recently observed intriguing mode splittings in a magnetic field with inelastic neutron scattering in the spin ladder compound (C_{5}H_{12}N)_{2}CuBr_{4} (BPCB), we investigate the nature of the spin ladder excitations using a density matrix renormalization group and analytical arguments. Starting from the fully frustrated ladder, for which we derive the low-energy spectrum, we show that bound states are generically present close to k=0 in the dynamical structure factor of spin ladders above H_{c1}, and that they are characterized by a field-independent binding energy and an intensity that grows with H-H_{c1}. These predictions are shown to explain quantitatively the split modes observed in BPCB.
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Affiliation(s)
- Mithilesh Nayak
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Dominic Blosser
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Andrey Zheludev
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Frédéric Mila
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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30
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Jafari R, Mahdavifar S, Akbari A. Geometrically frustrated anisotropic four-leg spin-1/2 nanotube. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:495601. [PMID: 31412325 DOI: 10.1088/1361-648x/ab3b45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We develop a real space quantum renormalization group (QRG) to explore a frustrated anisotropic four-leg spin-1/2 nanotube in the thermodynamic limit. We obtain the phase diagram, fixed points, critical points, the scaling of coupling constants and magnetization curves. Our investigation points out that, in the case of strong leg coupling, the diagonal frustrating interaction is marginal under QRG transformations and does not affect the universality class of the model. Remarkably, the renormalization equations express that the spin nanotube prepared in the strong leg coupling case goes to the strong plaquette coupling limit (weakly interacting plaquettes). Subsequently, in the limit of weakly interacting plaquettes, the model is mapped onto a 1D spin-1/2 XXZ chain in a longitudinal magnetic field under QRG transformation. Furthermore, the effective Hamiltonian of the spin nanotube inspires both first and second order phase transitions accompanied by the fractional magnetization plateaus. Our results show that the anisotropy changes the magnetization curve and the phase transition points, significantly. Finally, we report the numerical exact diagonalization results to compare the ground state phase diagram with our analytical visions.
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Affiliation(s)
- R Jafari
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran. Department of Physics, University of Gothenburg, SE 412 96 Gothenburg, Sweden. Beijing Computational Science Research Center, Beijing 100094, People's Republic of China
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31
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Robinson NJ, Johnson PD, Rice TM, Tsvelik AM. Anomalies in the pseudogap phase of the cuprates: competing ground states and the role of umklapp scattering. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:126501. [PMID: 31300626 DOI: 10.1088/1361-6633/ab31ed] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Over the past two decades, advances in computational algorithms have revealed a curious property of the two-dimensional Hubbard model (and related theories) with hole doping: the presence of close-in-energy competing ground states that display very different physical properties. On the one hand, there is a complicated state exhibiting intertwined spin, charge, and pair density wave orders. We call this 'type A'. On the other hand, there is a uniform d-wave superconducting state that we denote as 'type B'. We advocate, with the support of both microscopic theoretical calculations and experimental data, dividing the high-temperature cuprate superconductors into two corresponding families, whose properties reflect either the type A or type B ground states at low temperatures. We review the anomalous properties of the pseudogap phase that led us to this picture, and present a modern perspective on the role that umklapp scattering plays in these phenomena in the type B materials. This reflects a consistent framework that has emerged over the last decade, in which Mott correlations at weak coupling drive the formation of the pseudogap. We discuss this development, recent theory and experiments, and open issues.
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Affiliation(s)
- Neil J Robinson
- Institute for Theoretical Physics, University of Amsterdam, Science Park 904, Postbus 94485, 1098 XH Amsterdam, The Netherlands
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32
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Jiang HC, Devereaux TP. Superconductivity in the doped Hubbard model and its interplay with next-nearest hopping
t
′. Science 2019; 365:1424-1428. [DOI: 10.1126/science.aal5304] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/20/2019] [Indexed: 11/02/2022]
Affiliation(s)
- Hong-Chen Jiang
- Stanford Institute for Materials and Energy Sciences, SLAC and Stanford University, Menlo Park, CA 94025, USA
| | - Thomas P. Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC and Stanford University, Menlo Park, CA 94025, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
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33
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Ye Y, Ge ZY, Wu Y, Wang S, Gong M, Zhang YR, Zhu Q, Yang R, Li S, Liang F, Lin J, Xu Y, Guo C, Sun L, Cheng C, Ma N, Meng ZY, Deng H, Rong H, Lu CY, Peng CZ, Fan H, Zhu X, Pan JW. Propagation and Localization of Collective Excitations on a 24-Qubit Superconducting Processor. PHYSICAL REVIEW LETTERS 2019; 123:050502. [PMID: 31491305 DOI: 10.1103/physrevlett.123.050502] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Indexed: 06/10/2023]
Abstract
Superconducting circuits have emerged as a powerful platform of quantum simulation, especially for emulating the dynamics of quantum many-body systems, because of their tunable interaction, long coherence time, and high-precision control. Here in experiments, we construct a Bose-Hubbard ladder with a ladder array of 20 qubits on a 24-qubit superconducting processor. We investigate theoretically and demonstrate experimentally the dynamics of single- and double-excitation states with distinct behaviors, indicating the uniqueness of the Bose-Hubbard ladder. We observe the linear propagation of photons in the single-excitation case, satisfying the Lieb-Robinson bounds. The double-excitation state, initially placed at the edge, localizes; while placed in the bulk, it splits into two single-excitation modes spreading linearly toward two boundaries, respectively. Remarkably, these phenomena, studied both theoretically and numerically as unique properties of the Bose-Hubbard ladder, are represented coherently by pairs of controllable qubits in experiments. Our results show that collective excitations, as a single mode, are not free. This work paves the way to simulation of exotic logic particles by subtly encoding physical qubits and exploration of rich physics by superconducting circuits.
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Affiliation(s)
- Yangsen Ye
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Zi-Yong Ge
- Beijing National laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Yulin Wu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Shiyu Wang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Ming Gong
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Yu-Ran Zhang
- Beijing Computational Science Research Center, Beijing 100193, China
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Qingling Zhu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Rui Yang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Shaowei Li
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Futian Liang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Jin Lin
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Yu Xu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Cheng Guo
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Lihua Sun
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Chen Cheng
- Beijing Computational Science Research Center, Beijing 100193, China
- Center of Interdisciplinary Studies, Lanzhou University, Lanzhou 730000, China
| | - Nvsen Ma
- Beijing National laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zi Yang Meng
- Beijing National laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Hui Deng
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Hao Rong
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Chao-Yang Lu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Cheng-Zhi Peng
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Heng Fan
- Beijing National laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Xiaobo Zhu
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
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34
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Abstract
In this review article we consider theoretically and give experimental support to the models of the Fermi-Bose mixtures and the BCS-BEC (Bardeen Cooper Schrieffer–Bose Einstein) crossover compared with the strong-coupling approach, which can serve as the cornerstones on the way from high-temperature to room-temperature superconductivity in pressurized metallic hydrides. We discuss some key theoretical ideas and mechanisms proposed for unconventional superconductors (cuprates, pnictides, chalcogenides, bismuthates, diborides, heavy-fermions, organics, bilayer graphene, twisted graphene, oxide hetero-structures), superfluids and balanced or imbalanced ultracold Fermi gases in magnetic traps. We build a bridge between unconventional superconductors and recently discovered pressurized hydrides superconductors H3S and LaH10 with the critical temperature close to room temperature. We discuss systems with a line of nodal Dirac points close to the Fermi surface and superconducting shape resonances, and hyperbolic superconducting networks which are very important for the development of novel topological superconductors, for the energetics, for the applications in nano-electronics and quantum computations.
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Karlubíková P, Růžičková H, Chaloupka J, Munzar D. Pseudogap in the c-axis (along the ladder) optical conductivity of t - J ladders and its quasiparticle interpretation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:135502. [PMID: 30625439 DOI: 10.1088/1361-648x/aafd10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Motivated by similarities between cuprate superconductors and two-leg ladder copper-oxide compounds and in order to obtain a better understanding of optical properties of cuprate superconductors we have studied the c-axis (along the ladder) optical conductivity [Formula: see text] of a doped [Formula: see text] two-leg ladder. Using exact diagonalization, we have calculated the conductivity and related quantities for cyclic ladders of up to 13 rungs. In agreement with results of an early study by Hayward and coworkers (Hayward et al 1996 Phys. Rev. B 53 8863) we find that [Formula: see text] consists of a Drude peak at zero frequency and an absorption band in the infrared region that is separated from the former by a pseudogap. The width of the pseudogap [Formula: see text] increases with increasing J/t, in parallel with an increase of the magnitude [Formula: see text] of the gap in the quasiparticle excitation spectra. Our central finding is that [Formula: see text], where [Formula: see text] is the magnitude of the gap in the spin excitation spectra. We demonstrate that this approximate relation can be understood in terms of a phenomenological model involving a superconducting ladder and a coupling between charged quasiparticles and spin excitations. The relation is remarkably similar to the one between experimental values of the energy scale of a dip in the in-plane optical conductivity, the superconducting gap [Formula: see text] and the energy of the spin-resonance in cuprate superconductors (for a recent discussion of the optical data, see Šopík et al 2015 New J. Phys. 17 053022). Our findings support the point of view that low energy infrared active excited states of cuprate superconductors can be viewed as consisting of two charged quasiparticles connected with pair-breaking and a spin excitation.
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Affiliation(s)
- Paulína Karlubíková
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
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36
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Thermodynamics and Magnetic Excitations in Quantum Spin Trimers: Applications for the Understanding of Molecular Magnets. CRYSTALS 2019. [DOI: 10.3390/cryst9020093] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Molecular magnets provide a playground of interesting phenomena and interactions that have direct applications for quantum computation and magnetic systems. A general understanding of the underlying geometries for molecular magnets therefore generates a consistent foundation for which further analysis and understanding can be established. Using a Heisenberg spin-spin exchange Hamiltonian, we investigate the evolution of magnetic excitations and thermodynamics of quantum spin isosceles trimers (two sides J and one side α J ) with increasing spin. For the thermodynamics, we produce exact general solutions for the energy eigenstates and spin decomposition, which can be used to determine the heat capacity and magnetic susceptibility quickly. We show how the thermodynamic properties change with α coupling parameters and how the underlying ground state governs the Schottky anomaly. Furthermore, we investigate the microscopic excitations by examining the inelastic neutron scattering excitations and structure factors. Here, we illustrate how the individual dimer subgeometry governs the ability for probing underlying excitations. Overall, we feel these calculations can help with the general analysis and characterization of molecular magnet systems.
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37
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Robinson NJ, Altland A, Egger R, Gergs NM, Li W, Schuricht D, Tsvelik AM, Weichselbaum A, Konik RM. Nontopological Majorana Zero Modes in Inhomogeneous Spin Ladders. PHYSICAL REVIEW LETTERS 2019; 122:027201. [PMID: 30720312 DOI: 10.1103/physrevlett.122.027201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/10/2018] [Indexed: 06/09/2023]
Abstract
We show that the coupling of homogeneous Heisenberg spin-1/2 ladders in different phases leads to the formation of interfacial zero energy Majorana bound states. Unlike Majorana bound states at the interfaces of topological quantum wires, these states are void of topological protection and generally susceptible to local perturbations of the host spin system. However, a key message of our Letter is that, in practice, they show a high degree of resilience over wide parameter ranges which may make them interesting candidates for applications.
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Affiliation(s)
- Neil J Robinson
- Institute for Theoretical Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- CMPMS Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Alexander Altland
- Institut für Theoretische Physik, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany
| | - Reinhold Egger
- Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
| | - Niklas M Gergs
- Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands
| | - Wei Li
- Department of Physics, International Research Institute of Multidisciplinary Science, Beihang University, Beijing 100191, China
- Physics Department, Arnold Sommerfeld Center for Theoretical Physics, and Center for NanoScience, Ludwig-Maximilians-Universität, 80333 Munich, Germany
| | - Dirk Schuricht
- Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands
| | - Alexei M Tsvelik
- CMPMS Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Andreas Weichselbaum
- CMPMS Division, Brookhaven National Laboratory, Upton, New York 11973, USA
- Physics Department, Arnold Sommerfeld Center for Theoretical Physics, and Center for NanoScience, Ludwig-Maximilians-Universität, 80333 Munich, Germany
| | - Robert M Konik
- CMPMS Division, Brookhaven National Laboratory, Upton, New York 11973, USA
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38
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Salomon G, Koepsell J, Vijayan J, Hilker TA, Nespolo J, Pollet L, Bloch I, Gross C. Direct observation of incommensurate magnetism in Hubbard chains. Nature 2018; 565:56-60. [DOI: 10.1038/s41586-018-0778-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 10/12/2018] [Indexed: 11/10/2022]
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39
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Hörmann M, Wunderlich P, Schmidt KP. Dynamic Structure Factor of Disordered Quantum Spin Ladders. PHYSICAL REVIEW LETTERS 2018; 121:167201. [PMID: 30387667 DOI: 10.1103/physrevlett.121.167201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Indexed: 06/08/2023]
Abstract
We investigate the impact of quenched disorder on the zero-temperature dynamic structure factor of two-leg quantum spin ladders. Using linked-cluster expansions and bond-operator mean-field theory, huge effects on individual quasiparticles but also on composite bound states and two-quasiparticle continua are observed. This leads to intriguing quantum structures in dynamical correlation functions well observable in spectroscopic experiments.
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Affiliation(s)
- Max Hörmann
- Institute for Theoretical Physics, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Paul Wunderlich
- Institute for Theoretical Physics, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - K P Schmidt
- Institute for Theoretical Physics, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany
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40
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Silva CP, Junior HC, Santos IF, Bernardino AM, Cassaro RA, Novak MA, Vaz MG, Guedes GP. Synthesis, crystal structure, magnetic properties and DFT calculations of a mononuclear copper(II) complex: Relevance of halogen bonding for magnetic interaction. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2018.06.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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41
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Wehinger B, Fiolka C, Lanza A, Scatena R, Kubus M, Grockowiak A, Coniglio WA, Graf D, Skoulatos M, Chen JH, Gukelberger J, Casati N, Zaharko O, Macchi P, Krämer KW, Tozer S, Mudry C, Normand B, Rüegg C. Giant Pressure Dependence and Dimensionality Switching in a Metal-Organic Quantum Antiferromagnet. PHYSICAL REVIEW LETTERS 2018; 121:117201. [PMID: 30265101 DOI: 10.1103/physrevlett.121.117201] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Indexed: 06/08/2023]
Abstract
We report an extraordinary pressure dependence of the magnetic interactions in the metal-organic system [CuF_{2}(H_{2}O)_{2}]_{2}pyrazine. At zero pressure, this material realizes a quasi-two-dimensional spin-1/2 square-lattice Heisenberg antiferromagnet. By high-pressure, high-field susceptibility measurements we show that the dominant exchange parameter is reduced continuously by a factor of 2 on compression. Above 18 kbar, a phase transition occurs, inducing an orbital re-ordering that switches the dimensionality, transforming the quasi-two-dimensional lattice into weakly coupled chains. We explain the microscopic mechanisms for both phenomena by combining detailed x-ray and neutron diffraction studies with quantitative modeling using spin-polarized density functional theory.
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Affiliation(s)
- B Wehinger
- Department of Quantum Matter Physics, University of Geneva, 24, Quai Ernest Ansermet, CH-1211 Genève, Switzerland
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - C Fiolka
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - A Lanza
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - R Scatena
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - M Kubus
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - A Grockowiak
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - W A Coniglio
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - D Graf
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - M Skoulatos
- Heinz-Maier-Leibnitz Zentrum and Physics Department, Technische Universität München, Lichtenbergstrasse 1, 85748 Garching, Germany
| | - J-H Chen
- Condensed Matter Theory Group, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
- Theoretical Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J Gukelberger
- Theoretical Physics, ETH Zürich, CH-8093 Zürich, Switzerland
- Département de Physique and Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
| | - N Casati
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - O Zaharko
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - P Macchi
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - K W Krämer
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - S Tozer
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - C Mudry
- Condensed Matter Theory Group, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - B Normand
- Neutrons and Muons Research Division, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - Ch Rüegg
- Department of Quantum Matter Physics, University of Geneva, 24, Quai Ernest Ansermet, CH-1211 Genève, Switzerland
- Neutrons and Muons Research Division, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
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42
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Abstract
Iron-based superconductors display a variety of magnetic phases originating in the competition between electronic, orbital, and spin degrees of freedom. Previous theoretical investigations of the multi-orbital Hubbard model in one-dimension revealed the existence of an orbital-selective Mott phase (OSMP) with block spin order. Recent inelastic neutron scattering (INS) experiments on the BaFe2Se3 ladder compound confirmed the relevance of the block-OSMP. Moreover, the powder INS spectrum revealed an unexpected structure, containing both low-energy acoustic and high-energy optical modes. Here we present the theoretical prediction for the dynamical spin structure factor within a block-OSMP regime using the density-matrix renormalization-group method. In agreement with experiments, we find two dominant features: low-energy dispersive and high-energy dispersionless modes. We argue that the former represents the spin-wave-like dynamics of the block ferromagnetic islands, while the latter is attributed to a novel type of local on-site spin excitations controlled by the Hund coupling. Exploring the orbital-selective Mott phase (OSMP) addresses the central issue of electron correlations in the iron-based superconductors. Here the authors theoretically study the dynamical spin structure factor in the block-OSMP regime and unveil momentum dependent characteristics for different spin excitation modes.
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43
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Murakami T, Yamamoto T, Kumar A, Yusuf SM, Kageyama H. Conical-to-ferromagnetic phase conversion induced by cation order–disorder transition in Hf1–Ti MnSb2. J SOLID STATE CHEM 2018. [DOI: 10.1016/j.jssc.2018.04.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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44
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Mosadeq H, Asgari R. Two-leg ladder systems with dipole-dipole Fermion interactions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:205601. [PMID: 29589588 DOI: 10.1088/1361-648x/aaba30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The ground-state phase diagram of a two-leg fermionic dipolar ladder with inter-site interactions is studied using density matrix renormalization group (DMRG) techniques. We use a state-of-the-art implementation of the DMRG algorithm and finite size scaling to simulate large system sizes with high accuracy. We also consider two different model systems and explore stable phases in half and quarter filling factors. We find that in the half filling, the charge and spin gaps emerge in a finite value of the dipole-dipole and on-site interactions. In the quarter filling case, s-wave superconducting state, charge density wave, homogenous insulating and phase separation phases occur depend on the interaction values. Moreover, in the dipole-dipole interaction, the D-Mott phase emerges when the hopping terms along the chain and rung are the same, whereas, this phase has been only proposed for the anisotropic Hubbard model. In the half filling case, on the other hand, there is either charge-density wave or charged Mott order phase depends on the orientation of the dipole moments of the particles with respect to the ladder geometry.
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Affiliation(s)
- Hamid Mosadeq
- Department of physics, Faculty of Science, Shahrekord university, Shahrekord 88186-34141, Iran. School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran
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45
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Sousa HS, Pereira MSS, de Oliveira IN, Strečka J, Lyra ML. Phase diagram and re-entrant fermionic entanglement in a hybrid Ising-Hubbard ladder. Phys Rev E 2018; 97:052115. [PMID: 29906985 DOI: 10.1103/physreve.97.052115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Indexed: 06/08/2023]
Abstract
The degree of fermionic entanglement is examined in an exactly solvable Ising-Hubbard ladder, which involves interacting electrons on the ladder's rungs described by Hubbard dimers at half-filling on each rung, accounting for intrarung hopping and Coulomb terms. The coupling between neighboring Hubbard dimers is assumed to have an Ising-like nature. The ground-state phase diagram consists of four distinct regions corresponding to the saturated paramagnetic, the classical antiferromagnetic, the quantum antiferromagnetic, and the mixed classical-quantum phase. We have exactly computed the fermionic concurrence, which measures the degree of quantum entanglement between the pair of electrons on the ladder rungs. The effects of the hopping amplitude, the Coulomb term, temperature, and magnetic fields on the fermionic entanglement are explored in detail. It is shown that the fermionic concurrence displays a re-entrant behavior when quantum entanglement is being generated at moderate temperatures above the classical saturated paramagnetic ground state.
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Affiliation(s)
- H S Sousa
- Instituto de Física, Universidade Federal de Alagoas 57072-970 Maceió, Alagoas, Brazil
- Instituto Federal do Piauí, Campus Pedro II, 64255-000 Pedro II-Piauí, Brazil
| | - M S S Pereira
- Instituto de Física, Universidade Federal de Alagoas 57072-970 Maceió, Alagoas, Brazil
| | - I N de Oliveira
- Instituto de Física, Universidade Federal de Alagoas 57072-970 Maceió, Alagoas, Brazil
| | - J Strečka
- Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 040 01 Košice, Slovakia
| | - M L Lyra
- Instituto de Física, Universidade Federal de Alagoas 57072-970 Maceió, Alagoas, Brazil
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46
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Regnault LP, Boullier C, Lorenzo J. Polarized-neutron investigation of magnetic ordering and spin dynamics in BaCo 2(AsO 4) 2 frustrated honeycomb-lattice magnet. Heliyon 2018; 4:e00507. [PMID: 29560426 PMCID: PMC5857630 DOI: 10.1016/j.heliyon.2018.e00507] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/12/2017] [Accepted: 01/07/2018] [Indexed: 11/24/2022] Open
Abstract
The magnetic properties of the cobaltite BaCo2(AsO4)2, a good realization of the quasi two-dimensional frustrated honeycomb-lattice system with strong planar anisotropy, have been reinvestigated by means of spherical neutron polarimetry with CRYOPAD. From accurate measurements of polarization matrices both on elastic and inelastic contributions as a function of the scattering vector Q, we have been able to determine the low-temperature magnetic structure of BaCo2(AsO4)2 and reveal its puzzling in-plane spin dynamics. Surprisingly, the ground-state structure (described by an incommensurate propagation vector [Formula: see text], with [Formula: see text] and [Formula: see text]) appears to be a quasi-collinear structure, and not a simple helix, as previously determined. In addition, our results have revealed the existence of a non-negligible out-of-plane moment component [Formula: see text]/Co2+, representing about 10% of the in-plane component, as demonstrated by the presence of finite off-diagonal elements [Formula: see text] and [Formula: see text] of the polarization matrix, both on elastic and inelastic magnetic contributions. Despite a clear evidence of the existence of a slightly inelastic contribution of structural origin superimposed to the magnetic excitations at the scattering vectors [Formula: see text] and [Formula: see text] (energy transfer [Formula: see text] meV), no strong inelastic nuclear-magnetic interference terms could be detected so far, meaning that the nuclear and magnetic degrees of freedom have very weak cross-correlations. The strong inelastic [Formula: see text] and [Formula: see text] matrix elements can be understood by assuming that the magnetic excitations in BaCo2(AsO4)2 are spin waves associated with trivial anisotropic precessions of the magnetic moments involved in the canted incommensurate structure.
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Affiliation(s)
- L.-P. Regnault
- Institut Laue Langevin, 71 avenue des Martyrs, 38042 Grenoble cedex 9, France
| | - C. Boullier
- BNP-Paribas, 20 boulevard des Italiens, 75009 Paris, France
| | - J.E. Lorenzo
- Institut Néel-CNRS/UJF, F-38042 Grenoble, Cedex 9, France
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47
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Makarova TL, Shelankov AL, Shames AI, Zyrianova AA, Komlev AA, Chekhova GN, Pinakov DV, Bulusheva LG, Okotrub AV, Lähderanta E. Tabby graphene: Dimensional magnetic crossover in fluorinated graphite. Sci Rep 2017; 7:16544. [PMID: 29185456 PMCID: PMC5707391 DOI: 10.1038/s41598-017-16321-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 11/08/2017] [Indexed: 11/21/2022] Open
Abstract
Tabby is a pattern of short irregular stripes, usually related to domestic cats. We have produced Tabby patterns on graphene by attaching fluorine atoms running as monoatomic chains in crystallographic directions. Separated by non-fluorinated sp 2 carbon ribbons, sp 3-hybridized carbon atoms bonded to zigzag fluorine chains produce sp 2-sp 3 interfaces and spin-polarized edge states localized on both sides of the chains. We have compared two kinds of fluorinated graphite samples C2F x , with x near to 1 and x substantially below 1. The magnetic susceptibility of C2F x (x < 1) shows a broad maximum and a thermally activated spin gap behaviour that can be understood in a two-leg spin ladder model with ferromagnetic legs and antiferromagnetic rungs; the spin gap constitutes about 450 K. Besides, stable room-temperature ferromagnetism is observed in C2F x (x < 1) samples: the crossover to a three-dimensional magnetic behaviour is due to the onset of interlayer interactions. Similarly prepared C2F x (x ≈ 1) samples demonstrate features of two-dimensional magnetism without signs of high-temperature magnetic ordering, but with transition to a superparamagnetic state below 40 K instead. The magnetism of the Tabby graphene is stable until 520 K, which is the temperature of the structural reconstruction of fluorinated graphite.
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Affiliation(s)
- T L Makarova
- Lappeenranta University of Technology, Lappeenranta, 53851, Finland
- Ioffe Institute, St. Petersburg, 194021, Russian Federation
| | - A L Shelankov
- Ioffe Institute, St. Petersburg, 194021, Russian Federation
| | - A I Shames
- Ben-Gurion University of the Negev, Be'er-Sheva, 8410501, Israel
| | - A A Zyrianova
- St. Petersburg State University, St. Petersburg, 199034, Russian Federation
| | - A A Komlev
- Lappeenranta University of Technology, Lappeenranta, 53851, Finland
| | - G N Chekhova
- Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, 630090, Russian Federation
| | - D V Pinakov
- Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, 630090, Russian Federation
- Novosibirsk State University, Novosibirsk, 630090, Russian Federation
| | - L G Bulusheva
- Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, 630090, Russian Federation
- Novosibirsk State University, Novosibirsk, 630090, Russian Federation
| | - A V Okotrub
- Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, 630090, Russian Federation
- Novosibirsk State University, Novosibirsk, 630090, Russian Federation
| | - E Lähderanta
- Lappeenranta University of Technology, Lappeenranta, 53851, Finland.
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48
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Carvalho RCP, Pereira MSS, de Oliveira IN, Strečka J, Lyra ML. Ground-state phase diagram, fermionic entanglement and kinetically-induced frustration in a hybrid ladder with localized spins and mobile electrons. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:365801. [PMID: 28675150 DOI: 10.1088/1361-648x/aa7d61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We introduce an exactly solvable hybrid spin-ladder model containing localized nodal Ising spins and interstitial mobile electrons, which are allowed to perform a quantum-mechanical hopping between the ladder's legs. The quantum-mechanical hopping process induces an antiferromagnetic coupling between the ladder's legs that competes with a direct exchange coupling of the nodal spins. The model is exactly mapped onto the Ising spin ladder with temperature-dependent two- and four-spin interactions, which is subsequently solved using the transfer-matrix technique. We report the ground-state phase diagram and compute the fermionic concurrence to characterize the quantum entanglement between the pair of interstitial mobile electrons. We further provide a detailed analysis of the local spin ordering including the pair and four-spin correlation functions around an elementary plaquette, as well as, the local ordering diagrams. It is shown that a complex sequence of distinct local orderings and frustrated correlations takes place when the model parameters drive the investigated system close to a zero-temperature triple coexistence point.
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Affiliation(s)
- R C P Carvalho
- Instituto de Física, Universidade Federal de Alagoas 57072-970 Maceió-AL, Brazil
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Danilovich IL, Karpova EV, Morozov IV, Ushakov AV, Streltsov SV, Shakin AA, Volkova OS, Zvereva EA, Vasiliev AN. Spin-singlet Quantum Ground State in Zigzag Spin Ladder Cu(CF 3 COO) 2. Chemphyschem 2017; 18:2482-2486. [PMID: 28726353 DOI: 10.1002/cphc.201700707] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 07/18/2017] [Indexed: 11/09/2022]
Abstract
The copper salt of trifluoroacetic acid, Cu(CF3 COO)2 , offers a new platform to investigate the quantum ground states of low-dimensional magnets. In practice, it realizes the ideal case of a solid hosting essentially isolated magnetic monolayers. These entities are constituted by well-separated two-leg half-integer spin ladders organized in a zigzag fashion. The ladders are comprised of dimeric units of edge-sharing tetragonal pyramids coupled through carbon ions. The spin-gap state in this compound was revealed by static and dynamic magnetic measurements. No indications of long range magnetic ordering down to liquid helium temperature were obtained in specific heat measurements. First principles calculations allow estimation of the main exchange interaction parameters, J⊥ =176 K and J∥ =12 K, consistent with the weakly interacting dimers model.
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Affiliation(s)
| | | | | | - Alexey V Ushakov
- Institute of Metal Physics, Russian Academy of Sciences, Ekaterinburg, 620041, Russia
| | - Sergey V Streltsov
- Institute of Metal Physics, Russian Academy of Sciences, Ekaterinburg, 620041, Russia.,Ural Federal University, Ekaterinburg, 620002, Russia
| | - Alexander A Shakin
- National University of Science and Technology "MISiS", Moscow, 119049, Russia
| | - Olga S Volkova
- Moscow State University, Moscow, 119991, Russia.,Ural Federal University, Ekaterinburg, 620002, Russia.,National University of Science and Technology "MISiS", Moscow, 119049, Russia
| | - Elena A Zvereva
- Moscow State University, Moscow, 119991, Russia.,National Research South Ural State University, Chelyabinsk, 454080, Russia
| | - Alexander N Vasiliev
- Moscow State University, Moscow, 119991, Russia.,National University of Science and Technology "MISiS", Moscow, 119049, Russia.,National Research South Ural State University, Chelyabinsk, 454080, Russia
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50
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Ward S, Mena M, Bouillot P, Kollath C, Giamarchi T, Schmidt KP, Normand B, Krämer KW, Biner D, Bewley R, Guidi T, Boehm M, McMorrow DF, Rüegg C. Bound States and Field-Polarized Haldane Modes in a Quantum Spin Ladder. PHYSICAL REVIEW LETTERS 2017; 118:177202. [PMID: 28498681 DOI: 10.1103/physrevlett.118.177202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Indexed: 06/07/2023]
Abstract
The challenge of one-dimensional systems is to understand their physics beyond the level of known elementary excitations. By high-resolution neutron spectroscopy in a quantum spin-ladder material, we probe the leading multiparticle excitation by characterizing the two-magnon bound state at zero field. By applying high magnetic fields, we create and select the singlet (longitudinal) and triplet (transverse) excitations of the fully spin-polarized ladder, which have not been observed previously and are close analogs of the modes anticipated in a polarized Haldane chain. Theoretical modeling of the dynamical response demonstrates our complete quantitative understanding of these states.
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Affiliation(s)
- S Ward
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
- Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva, Switzerland
| | - M Mena
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
- Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva, Switzerland
| | - P Bouillot
- Department of Medical Imaging and Information Sciences, Interventional Neuroradiology Unit, University Hospitals of Geneva, CH-1211 Geneva, Switzerland
- Laboratory for Hydraulic Machines, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - C Kollath
- Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva, Switzerland
- HISKP, University of Bonn, Nussallee 14-16, 53115 Bonn, Germany
| | - T Giamarchi
- Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva, Switzerland
| | - K P Schmidt
- Theoretische Physik I, Staudtstrasse 7, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - B Normand
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - K W Krämer
- Department of Chemistry and Biochemistry, University of Bern, CH-3012 Bern, Switzerland
| | - D Biner
- Department of Chemistry and Biochemistry, University of Bern, CH-3012 Bern, Switzerland
| | - R Bewley
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxford OX11 0QX, United Kingdom
| | - T Guidi
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxford OX11 0QX, United Kingdom
| | - M Boehm
- Institut Laue Langevin, 6 rue Jules Horowitz BP156, 38024 Grenoble CEDEX 9, France
| | - D F McMorrow
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - Ch Rüegg
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva, Switzerland
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