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Zhang Z, Porter AP, Sun Y, Belashchenko KD, Viswanathan G, Sarkar A, Gamage EH, Kovnir K, Ho KM, Antropov V. Unveiling a Family of Dimerized Quantum Magnets, Conventional Antiferromagnets, and Nonmagnets in Ternary Metal Borides. J Am Chem Soc 2024. [PMID: 38832750 DOI: 10.1021/jacs.4c05478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Dimerized quantum magnets are exotic crystalline materials where Bose-Einstein condensation of magnetic excitations can happen. However, known dimerized quantum magnets are limited to only a few oxides and halides. Here, we unveil 9 dimerized quantum magnets and 11 conventional antiferromagnets in ternary metal borides MTB4 (M = Sc, Y, La, Ce, Lu, Mg, Ca, and Al; T = V, Cr, Mn, Fe, Co, and Ni), where T atoms are arranged in structural dimers. Quantum magnetism in these compounds is dominated by strong antiferromagnetic (AFM) interactions between Cr (Cr and Mn for M = Mg and Ca) atoms within the dimers, with much weaker interactions between the dimers. These systems are proposed to be close to a quantum critical point between a disordered singlet spin-dimer phase, with a spin gap, and the ordered conventional Néel AFM phase. They greatly enrich the materials inventory that allows investigations of the spin-gap phase. Conventional antiferromagnetism in these compounds is dominated by ferromagnetic Mn (Fe for M = Mg and Ca) interactions within the dimers. The predicted stable and nonmagnetic (NM) YFeB4 phase is synthesized and characterized, providing a scarce candidate to study Fe dimers and Fe ladders in borides. The identified quantum, conventional, and NM systems provide a platform with abundant possibilities to tune the magnetic exchange coupling by doping and study the unconventional quantum phase transition and conventional magnetic transitions. This work opens new avenues for studying novel magnetism in borides arising from spin dimers and establishes a theoretical workflow for future searches for dimerized quantum magnets in other families of materials.
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Affiliation(s)
- Zhen Zhang
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States
| | - Andrew P Porter
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- Ames National Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Yang Sun
- Department of Physics, Xiamen University, Xiamen 361005, China
| | - Kirill D Belashchenko
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Gayatri Viswanathan
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- Ames National Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Arka Sarkar
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- Ames National Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Eranga H Gamage
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- Ames National Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Kirill Kovnir
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- Ames National Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Kai-Ming Ho
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States
| | - Vladimir Antropov
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States
- Ames National Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
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Dai YW, Liu XJ, Li SH, Chen AM. Characteristic quantum phase in Heisenberg antiferromagnetic chain with exchange and single-ion anisotropies. Phys Rev E 2022; 106:054104. [PMID: 36559519 DOI: 10.1103/physreve.106.054104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/11/2022] [Indexed: 12/24/2022]
Abstract
We investigate the ground-state phase diagram for a spin-one quantum Heisenberg antiferromagnetic chain with exchange and single-ion anisotropies in an external magnetic field by using the infinite time-evolving block decimation algorithm to compute the ground-state fidelity per lattice site. We detect all phase boundaries solely by computing the ground-state fidelity per lattice site, with the prescription that a phase transition point is attributed to a pinch point on the ground-state fidelity surface. Furthermore, the results indicate that a magnetization plateau corresponds to a fidelity plateau on the ground-state fidelity surface, thus offering an alternative route for investigating the magnetization processes of quantum many-body spin systems. We characterize all phases by using the local-order parameter, the spin correlation, the momentum distribution of the spin correlation structure factor, and mutual information as a function of the lattice distance. The commensurate and incommensurate phases are distinguished by the mutual information. In addition, the central charges at criticalities are identified by performing a finite-entanglement scaling analysis. The results show that all phase transitions between spin liquids and magnetization plateaus belong to the Pokrovsky-Talapov universality class.
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Affiliation(s)
- Yan-Wei Dai
- Centre for Modern Physics and Department of Physics, Chongqing University, Chongqing 400044, The People's Republic of China.,State Key Laboratory of Optoelectronic Material and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, The People's Republic of China
| | - Xi-Jing Liu
- Centre for Modern Physics and Department of Physics, Chongqing University, Chongqing 400044, The People's Republic of China.,The School of Materials Science and Engineering, Chongqing Jiaotong University, Chongqing 400044, The People's Republic of China
| | - Sheng-Hao Li
- Centre for Modern Physics and Department of Physics, Chongqing University, Chongqing 400044, The People's Republic of China.,School of Big Data and Internet of Things, Chongqing Vocational Institute of Engineering, Chongqing 402260, The People's Republic of China
| | - Ai-Min Chen
- School of Science, Xi'an Polytechnic University, Xi'an 710048, The People's Republic of China
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Discovery of quantum phases in the Shastry-Sutherland compound SrCu 2(BO 3) 2 under extreme conditions of field and pressure. Nat Commun 2022; 13:2301. [PMID: 35484351 PMCID: PMC9050886 DOI: 10.1038/s41467-022-30036-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 04/07/2022] [Indexed: 11/22/2022] Open
Abstract
The 2-dimensional layered oxide material SrCu2(BO3)2, long studied as a realization of the Shastry-Sutherland spin topology, exhibits a range of intriguing physics as a function of both hydrostatic pressure and magnetic field, with a still debated intermediate plaquette phase appearing at approximately 20 kbar and a possible deconfined critical point at higher pressure. Here, we employ a tunnel diode oscillator (TDO) technique to probe the behavior in the combined extreme conditions of high pressure, high magnetic field, and low temperature. We reveal an extensive phase space consisting of multiple magnetic analogs of the elusive supersolid phase and a magnetization plateau. In particular, a 10 × 2 supersolid and a 1/5 plateau, identified by infinite Projected Entangled Pair States (iPEPS) calculations, are found to rely on the presence of both magnetic and non-magnetic particles in the sea of dimer singlets. These states are best understood as descendants of the full-plaquette phase, the leading candidate for the intermediate phase of SrCu2(BO3)2. SrCu2(BO3)2 is a 2D quantum antiferromagnet on a particular frustrated lattice showing multiple magnetization plateaus and quantum phase transitions under high pressure. Here the authors uncover novel magnetic phases in this material under combined effects of extreme magnetic field and pressure.
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Heydarinasab F, Abouie J. Mixed-spin system with supersolid phases: magnetocaloric effect and thermal properties. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:165804. [PMID: 31835260 DOI: 10.1088/1361-648x/ab61ca] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recently, it has been shown that two dimensional frustrated mixed-spin systems with anisotropic exchange interactions display supersolid phases in their ground state phase diagrams even in the absence of long-range interactions. In this paper, using cluster mean field theory, we investigate the effects of thermal fluctuations on the ground state phases of this kind of system and show that various thermal solids and thermal insulators emerge around the ground state solid and Mott insulating phases. We also study the thermodynamic properties and magnetocaloric effect of these systems and demonstrate that at low temperatures, a large cooling rate is seen in the vicinity of the solid-supersolid, solid-superfluid and Mott insulator-superfluid critical points, with the large accumulation of the entropy and the minimums of the isentropes. Our results show the sign change of the magnetocaloric parameter inside the solids and the Mott insulator, which is a characteristic of ordered phases.
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Affiliation(s)
- F Heydarinasab
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran. Department of Physics, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran
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Abstract
We study the ground state phase diagram of a two dimensional mixed-spin system of coupled alternating spin-1 and 1/2 chains with a stripe supersolid phase. Utilizing different analytical and numerical approaches such as mean field approximation, cluster mean field theory and linear spin wave theory, we demonstrate that our system displays a rich ground state phase diagram including novel stripe supersolid, solids with different fillings and super-counterfluid phases, in addition to a stripe solid with half filling, superfluid and Mott insulating phases. In order to find a minimal mixed-spin model for stripe supersolidity, in the second part of the paper we consider two kinds of mixed-spin system of coupled alternating spin-1 and 1/2 chains with (i) anisotropic nearest neighbor interactions, (ii) anisotropic hoppings and study their ground state phase diagrams. We demonstrate that, for the systems with uniform hoppings, the repulsive intra-chains interactions are necessary for stripe supersolidity. In this case the minimal two dimensional mixed-spin model is a system of spin-1 and spin-1/2 XXZ chains, interacting via Ising Hamiltonian. In the case of anisotropic hoppings, a system of coupled Ising chains is the minimal model.
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Wang Z, Quintero-Castro DL, Zherlitsyn S, Yasin S, Skourski Y, Islam ATMN, Lake B, Deisenhofer J, Loidl A. Field-Induced Magnonic Liquid in the 3D Spin-Dimerized Antiferromagnet Sr_{3}Cr_{2}O_{8}. PHYSICAL REVIEW LETTERS 2016; 116:147201. [PMID: 27104722 DOI: 10.1103/physrevlett.116.147201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Indexed: 06/05/2023]
Abstract
We report on ultrasound and magnetization studies in three-dimensional, spin-dimerized Sr_{3}Cr_{2}O_{8} as a function of temperature and external magnetic field up to 61 T. It is well established [A. A. Aczel et al., Phys. Rev. Lett. 103, 207203 (2009)] that this system exhibits a magnonic-superfluid phase between 30 and 60 T and below 8 K. By mapping ultrasound and magnetization anomalies as a function of magnetic field and temperature we establish that this superfluid phase is embedded in a domelike phase regime of a high-temperature magnonic liquid extending up to 18 K. Compared to thermodynamic results, our study indicates that the magnonic liquid could be characterized by an Ising-like order but has lost the coherence of the transverse components.
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Affiliation(s)
- Zhe Wang
- Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany
| | - D L Quintero-Castro
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany
| | - S Zherlitsyn
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden, Germany
| | - S Yasin
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden, Germany
| | - Y Skourski
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden, Germany
| | - A T M N Islam
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany
| | - B Lake
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany
- Institut für Festkörperphysik, Technische Universität Berlin, D-10623 Berlin, Germany
| | - J Deisenhofer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany
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Murakami Y, Werner P, Tsuji N, Aoki H. Supersolid phase accompanied by a quantum critical point in the intermediate coupling regime of the Holstein model. PHYSICAL REVIEW LETTERS 2014; 113:266404. [PMID: 25615362 DOI: 10.1103/physrevlett.113.266404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Indexed: 06/04/2023]
Abstract
We reveal that electron-phonon systems described by the Holstein model on a bipartite lattice exhibit, away from half filling, a supersolid (SS) phase characterized by coexisting charge order (CO) and superconductivity (SC), and an accompanying quantum critical point (QCP). The SS phase, demonstrated by the dynamical mean-field theory with a quantum Monte Carlo impurity solver, emerges in the intermediate-coupling regime, where the peak of the Tc dome is located and the metal-insulator crossover occurs. On the other hand, in the weak- and strong-coupling regimes the CO-SC boundary is of first order with no intervening SS phases. The QCP is associated with the continuous transition from SS to SC and characterized by a reentrant behavior of the SS around it. We further show that the SS-SC transition is hallmarked by diverging charge fluctuations and a kink (peak) in the superfluid density.
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Affiliation(s)
- Yuta Murakami
- Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Naoto Tsuji
- Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
| | - Hideo Aoki
- Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
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Wierschem K, Sengupta P. Quenching the haldane gap in spin-1 Heisenberg antiferromagnets. PHYSICAL REVIEW LETTERS 2014; 112:247203. [PMID: 24996106 DOI: 10.1103/physrevlett.112.247203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Indexed: 06/03/2023]
Abstract
We consider a quasi-one-dimensional system of spin-1 Heisenberg antiferromagnetic chains in two-dimensional and three-dimensional hypercubic lattices with interchain coupling J and uniaxial single-ion anisotropy D. Using large-scale numerical simulations, we map out the J-D phase diagram and investigate the low-lying excitations of the Haldane phase in the J≪1 limit. We also provide direct evidence that the Haldane phase remains a nontrivial symmetry-protected topological state for small but finite J.
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Affiliation(s)
- Keola Wierschem
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore and International Institute for Complex Adaptive Matter, University of California, Davis, California 95616, USA
| | - Pinaki Sengupta
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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9
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Wierschem K, Sengupta P. Columnar antiferromagnetic order and spin supersolid phase on the extended Shastry-Sutherland lattice. PHYSICAL REVIEW LETTERS 2013; 110:207207. [PMID: 25167448 DOI: 10.1103/physrevlett.110.207207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Indexed: 06/03/2023]
Abstract
We use large scale quantum Monte Carlo simulations to study an extended version of the canonical Shastry-Sutherland model--including additional interactions and exchange anisotropy--over a wide range of interaction parameters and an applied magnetic field. The model is appropriate for describing the low energy properties of some members of the rare earth tetraborides. Working in the limit of large Ising-like exchange anisotropy, we demonstrate the stabilization of columnar antiferromagnetic order in the ground state at zero field and an extended magnetization plateau at 1/2 the saturation magnetization in the presence of an applied longitudinal magnetic field--qualitatively similar to experimentally observed low-temperature phases in ErB(4). Our results show that for an optimal range of exchange parameters, a spin supersolid ground state is realized over a finite range of an applied field between the columnar antiferromagnetic phase and the magnetization plateau. The full momentum dependence of the longitudinal and transverse components of the static structure factor is calculated in the spin supersolid phase to demonstrate the simultaneous existence of diagonal and off-diagonal long-range order. Our results provide crucial guidance in designing further experiments to search for the interesting spin supersolid phase in ErB(4).
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Affiliation(s)
- Keola Wierschem
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Pinaki Sengupta
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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10
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Moskvin AS. Perspectives of disproportionation driven superconductivity in strongly correlated 3d compounds. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:085601. [PMID: 23363546 DOI: 10.1088/0953-8984/25/8/085601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Disproportionation in 3d compounds can give rise to an unconventional electron-hole Bose liquid with a very rich phase diagram, from a Bose metal, to a charge ordering insulator and an inhomogeneous Bose-superfluid. Optimal conditions for disproportionation driven high-T(c) superconductivity are shown to be realized only for several Jahn-Teller d(n) configurations that permit the formation of well defined local composite bosons. These are the high-spin d(4), low-spin d(7), and d(9) configurations given the octahedral crystal field, and the d(1), high-spin d(6) configurations given the tetrahedral crystal field. The disproportionation reaction has a peculiar 'anti-Jahn-Teller' character lifting the bare orbital degeneracy. Superconductivity in the d(4) and d(6) systems at variance with d(1), d(7), and d(9) systems implies unavoidable coexistence of the spin-triplet composite bosons and the magnetic lattice. We argue that unconventional high-T(c) superconductivity, observed in quasi-2d cuprates with tetragonally distorted CuO(6) octahedra and iron-based layered pnictides/chalcogenides with tetrahedrally coordinated Fe(2+) ions presents a key argument to support the fact that the disproportionation scenario is at work in these compounds.
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Affiliation(s)
- A S Moskvin
- Department of Theoretical Physics, Ural Federal University, 620083 Ekaterinburg, Russia.
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11
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Kohama Y, Wang S, Uchida A, Prsa K, Zvyagin S, Skourski Y, McDonald RD, Balicas L, Ronnow HM, Rüegg C, Jaime M. Anisotropic cascade of field-induced phase transitions in the frustrated spin-ladder system BiCu2PO6. PHYSICAL REVIEW LETTERS 2012; 109:167204. [PMID: 23215121 DOI: 10.1103/physrevlett.109.167204] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Indexed: 06/01/2023]
Abstract
BiCu(2)PO(6) is a frustrated two-leg spin-ladder compound with a spin gap that can be closed with a magnetic field of approximately 20 T. This quantum phase transition and its related phase diagram as a function of magnetic field and temperature (H, T) are investigated up to 60 T by means of specific heat, magnetocaloric effect, magnetization, and magnetostriction measurements. In contrast to other gapped quantum magnets, BiCu(2)PO(6) undergoes a series of unexpected first- and second-order phase transitions when an external magnetic field is applied along the crystallographic c axis. The application of a magnetic field along the b axis induces two second-order phase transitions. We propose that the anisotropy and complex phase diagram result from the interplay between strong geometrical frustration and spin-orbit interaction necessary for the description of this fascinating magnetic system.
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Affiliation(s)
- Yoshimitsu Kohama
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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12
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Ng KK, Chen YC, Tzeng YC. Quarter-filled supersolid and solid phases in the extended Bose-Hubbard model. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:185601. [PMID: 21393687 DOI: 10.1088/0953-8984/22/18/185601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We numerically study the ground state phase diagram of the two-dimensional hard-core Bose-Hubbard model with nearest-(V(1)) and next-nearest-neighbour (V(2)) repulsions. In particular, we focus on the quarter-filled phases where one supersolid and two solid phases are observed. Using both canonical and grand canonical quantum Monte Carlo (QMC) methods and a mean-field calculation, we provide evidence for the existence of a commensurate supersolid. Despite the two possible diagonal long-range orderings for the solid phase, only one kind of supersolid phase is found to be energetically stable. The competition between the two solid phases manifests itself as a first-order phase transition around 2V(2) ∼ V(1). The change of order parameters as a function of the chemical potential is also presented.
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Affiliation(s)
- Kwai-Kong Ng
- Department of Physics, Tunghai University, Taichung 40704, Taiwan
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14
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Bostrem IG, Sinitsyn VE, Ovchinnikov AS, Hosokoshi Y, Inoue K. Bose-Einstein condensation of semi-hard bosons in the S = 1 dimerized organic compound F(2)PNNNO. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:036001. [PMID: 21386299 DOI: 10.1088/0953-8984/22/3/036001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An analysis of the energy spectrum and magnetization curve of the two-dimensional organic antiferromagnet F(2)PNNNO with a spin-one dimerized structure shows that the behavior of the compound in an external magnetic field can be explained within a lattice boson model with an extended Pauli exclusion principle, i.e. no more than two bosons per dimer. The unusual magnetization curve observed experimentally in the compound reflects a sequence of phase transitions intrinsic for a lattice boson system with strong on-site and inter-site repulsions due to a tuning of magnon density by the applied magnetic field.
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Affiliation(s)
- I G Bostrem
- Department of Physics, Ural State University, 620083, Ekaterinburg, Russia
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15
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Samulon EC, Kohama Y, McDonald RD, Shapiro MC, Al-Hassanieh KA, Batista CD, Jaime M, Fisher IR. Asymmetric quintuplet condensation in the frustrated S = 1 spin dimer compound Ba3Mn2O8. PHYSICAL REVIEW LETTERS 2009; 103:047202. [PMID: 19659394 DOI: 10.1103/physrevlett.103.047202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 06/19/2009] [Indexed: 05/28/2023]
Abstract
Ba_{3}Mn_{2}O_{8} is a spin-dimer compound based on pairs of S = 1, 3d;{2}, Mn;{5+} ions arranged on a triangular lattice. Antiferromagnetic intradimer exchange leads to a singlet ground state in zero field, with excited triplet and quintuplet states at higher energy. High field thermodynamic measurements are used to establish the phase diagram, revealing a substantial asymmetry of the quintuplet condensate. This striking effect, all but absent for the triplet condensate, is due to a fundamental asymmetry in quantum fluctuations of the paramagnetic phases near the various critical fields.
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Affiliation(s)
- E C Samulon
- Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, California 94305, USA
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Raczkowski M, Poilblanc D. Supersolid phases of a doped valence-bond quantum antiferromagnet: evidence for a coexisting superconducting order parameter. PHYSICAL REVIEW LETTERS 2009; 103:027001. [PMID: 19659234 DOI: 10.1103/physrevlett.103.027001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Indexed: 05/28/2023]
Abstract
Motivated by numerical evidence of the valence-bond ground state of the two-dimensional Heisenberg pyrochlore lattice, we argue using a t-J model that it evolves under doping into novel phases characterized by superconductivity coexisting with the underlying valence-bond solid order. A fermionic mean-field theory supplemented by exact diagonalization results provide strong arguments in favor of the stability of such supersolid phases. The resemblance with modulated superconducting patterns in high-Tc cuprates as well as possible relevance to frustrated noncuprate superconductors such as spinels and pyrochlores is discussed.
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Affiliation(s)
- Marcin Raczkowski
- Marian Smoluchowski Institute of Physics, Jagellonian University, Reymonta 4, PL-30059 Kraków, Poland
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17
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Laflorencie N, Mila F. Theory of the field-induced BEC in the frustrated spin-1/2 dimer compound BaCuSi2O6. PHYSICAL REVIEW LETTERS 2009; 102:060602. [PMID: 19257573 DOI: 10.1103/physrevlett.102.060602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2008] [Revised: 01/07/2009] [Indexed: 05/27/2023]
Abstract
Building on recent neutron and NMR experiments, we investigate the field-induced exotic criticality observed in the frustrated compound BaCuSi2O6 using a frustrated model with two types of bilayers. A semiclassical treatment of the effective hard-core boson model shows that perfect interlayer frustration leads to a 2D-like critical exponent varphi=1 without logarithmic corrections and to a 3D low temperature phase with different but nonvanishing triplet populations in both types of bilayers. These further suggest a simple phenomenology in terms of a field-dependent transverse coupling in the context of which we reproduce the entire field-temperature phase diagram with quantum Monte Carlo simulations.
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Affiliation(s)
- Nicolas Laflorencie
- Laboratoire de Physique des Solides, Université Paris-Sud, UMR-8502 CNRS, 91405 Orsay, France
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Takigawa M, Matsubara S, Horvatić M, Berthier C, Kageyama H, Ueda Y. NMR evidence for the persistence of a spin superlattice beyond the 1/8 magnetization plateau in SrCu2(BO3)_{2}. PHYSICAL REVIEW LETTERS 2008; 101:037202. [PMID: 18764284 DOI: 10.1103/physrevlett.101.037202] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 04/13/2008] [Indexed: 05/26/2023]
Abstract
We present 11B NMR studies of the 2D frustrated dimer spin system SrCu2(BO3)_{2} in the field range 27-31 T covering the upper phase boundary of the 1/8 magnetization plateau, identified at 28.4 T. Our data provide a clear evidence that above 28.4 T the spin superlattice of the 1/8 plateau is modified but does not melt even though the magnetization increases. Although this is precisely what is expected for a supersolid phase, the microscopic nature of this new phase is much more complex. We discuss the field-temperature phase diagram on the basis of our NMR data.
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Affiliation(s)
- M Takigawa
- Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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Schmidt KP, Dorier J, Läuchli AM, Mila F. Supersolid phase induced by correlated hopping in spin-1/2 frustrated quantum magnets. PHYSICAL REVIEW LETTERS 2008; 100:090401. [PMID: 18352679 DOI: 10.1103/physrevlett.100.090401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Revised: 10/25/2007] [Indexed: 05/26/2023]
Abstract
We show that correlated hopping of triplets, which is often the dominant source of kinetic energy in dimer-based frustrated quantum magnets, produces a remarkably strong tendency to form supersolid phases in a magnetic field. These phases are characterized by simultaneous modulation and ordering of the longitudinal and transverse magnetization, respectively. Using quantum Monte Carlo and a semiclassical approach for an effective hard-core boson model with nearest-neighbor repulsion on a square lattice, we prove, in particular, that a supersolid phase can exist even if the repulsion is not strong enough to stabilize an insulating phase at half-filling. Experimental implications for frustrated quantum antiferromagnets in a magnetic field at zero and finite temperature are discussed.
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Affiliation(s)
- K P Schmidt
- Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne, CH 1015 Lausanne, Switzerland.
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Sengupta P, Batista CD. Spin supersolid in an anisotropic spin-one Heisenberg chain. PHYSICAL REVIEW LETTERS 2007; 99:217205. [PMID: 18233248 DOI: 10.1103/physrevlett.99.217205] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Indexed: 05/25/2023]
Abstract
We consider an S=1 Heisenberg chain with strong exchange (Delta=J(z)/J(perpendicular)) and single-ion uniaxial anisotropy (D) in a magnetic field (B) along the symmetry axis. The low-energy spectrum is described by an effective S=1/2 XXZ model that acts on two different low-energy sectors for a finite range of fields. The vacuum of each sector exhibits Ising-like antiferromagnetic ordering coexisting with the finite spin stiffness obtained from the exact solution of the XXZ model. In this way, we demonstrate the existence of a spin supersolid phase. We also compute the full Delta-B quantum phase diagram using a quantum Monte Carlo method.
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Affiliation(s)
- P Sengupta
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Laflorencie N, Mila F. Quantum and thermal transitions out of the supersolid phase of a 2D quantum antiferromagnet. PHYSICAL REVIEW LETTERS 2007; 99:027202. [PMID: 17678251 DOI: 10.1103/physrevlett.99.027202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Indexed: 05/16/2023]
Abstract
We investigate the thermodynamic properties of a field-induced supersolid phase in a 2D quantum antiferromagnet model. Using quantum Monte Carlo simulations, a very rich phase diagram is mapped out in the temperature-magnetic-field plane, with an extended supersolid region where a diagonal (solid) order coexists with a finite XY spin stiffness (superfluid). The various quantum and thermal transitions out of the supersolid state are characterized. Experimental consequences in the context of field-induced magnetization plateau materials are briefly discussed.
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Affiliation(s)
- Nicolas Laflorencie
- Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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