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Mohseni M, Allami H, Miravet D, Gayowsky DJ, Korkusinski M, Hawrylak P. Majorana Excitons in a Kitaev Chain of Semiconductor Quantum Dots in a Nanowire. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2293. [PMID: 37630878 PMCID: PMC10459495 DOI: 10.3390/nano13162293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023]
Abstract
We present here a theory of Majorana excitons, photo-excited conduction electron-valence band hole pairs, interacting with Majorana Fermions in a Kitaev chain of semiconductor quantum dots embedded in a nanowire. Using analytical tools and exact diagonalization methods, we identify the presence of Majorana zero modes in the nanowire absorption spectra.
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Affiliation(s)
- Mahan Mohseni
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (M.M.); (D.M.); (D.J.G.); (M.K.)
| | - Hassan Allami
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (M.M.); (D.M.); (D.J.G.); (M.K.)
| | - Daniel Miravet
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (M.M.); (D.M.); (D.J.G.); (M.K.)
| | - David J. Gayowsky
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (M.M.); (D.M.); (D.J.G.); (M.K.)
| | - Marek Korkusinski
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (M.M.); (D.M.); (D.J.G.); (M.K.)
- Security and Disruptive Technologies, National Research Council, Ottawa, ON K1A 0R6, Canada
| | - Pawel Hawrylak
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (M.M.); (D.M.); (D.J.G.); (M.K.)
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Yang Y, Wang QH. Exploring the 4d 1analogue of cuprates: theoretical studies on bulk NbF 4and NbF 4monolayer stabilized on MgO (001) plane. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:505503. [PMID: 36301710 DOI: 10.1088/1361-648x/ac9dd6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
The recent research in infinite-layer nickelates has inspired new effort in finding the cuprate analogs. Here we propose that NbF4, which contains niobium-centered fluorine octahedra, is a promising 4d1analogue of cuprates. Using the density functional theory, we first show that bulk NbF4is in close proximity tod1configuration, with Nb4dxyorbital nearly half-filled. A single band with dominating4dxycharacter crosses the Fermi level, forming a square-like Fermi surface. The intralayer G-type antiferromagnetic (AFM) order is energetically favored and the Coulomb interaction drives the system into an AFM insulator. Next we demonstrate that the NbF4layer can be stabilized on MgO substrate with main electronic and magnetic features retained, offering an alternative route to realize the NbF4-related high-Tcsuperconductors. Furthermore, we derive effective single orbital models for both systems and investigate the electron correlation effects via functional renormalization group. We find that the G-type AFM dominates near half-filling butdx2-y2-wave superconductivity (SC) prevails upon suitable hole/electron doping. Based on the striking similarities between NbF4and cuprates, we suggest that NbF4-related compounds may be exotic candidates for searching new high-Tcsuperconductors.
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Affiliation(s)
- Yang Yang
- College of Physics and Electronic Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, People's Republic of China
- Henan Key Laboratory of Magnetoelectronic Information Functional Materials, Zhengzhou University of Light Industry, Zhengzhou 450002, People's Republic of China
| | - Qiang-Hua Wang
- National Laboratory of Solid State Microstructures & School of Physics, Nanjing University, Nanjing 210093, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
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Ma MH, Batsaikhan E, Chen HN, Chen TY, Lee CH, Li WH, Wu CM, Wang CW. Non-conventional superconductivity in magnetic In and Sn nanoparticles. Sci Rep 2022; 12:775. [PMID: 35031677 PMCID: PMC8760274 DOI: 10.1038/s41598-022-04889-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/21/2021] [Indexed: 11/23/2022] Open
Abstract
We report on experimental evidence of non-conversional pairing in In and Sn nanoparticle assemblies. Spontaneous magnetizations are observed, through extremely weak-field magnetization and neutron-diffraction measurements, to develop when the nanoparticles enter the superconducting state. The superconducting transition temperature TC shifts to a noticeably higher temperature when an external magnetic field or magnetic Ni nanoparticles are introduced into the vicinity of the superconducting In or Sn nanoparticles. There is a critical magnetic field and a critical Ni composition that must be reached before the magnetic environment will suppress the superconductivity. The observations may be understood when assuming development of spin-parallel superconducting pairs on the surfaces and spin-antiparallel superconducting pairs in the core of the nanoparticles.
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Affiliation(s)
- Ma-Hsuan Ma
- Department of Physics, National Central University, Zhongli, 32001, Taiwan
| | | | - Huang-Nan Chen
- Department of Physics, National Central University, Zhongli, 32001, Taiwan
| | - Ting-Yang Chen
- Department of Physics, National Central University, Zhongli, 32001, Taiwan
| | - Chi-Hung Lee
- Department of Physics, National Central University, Zhongli, 32001, Taiwan
| | - Wen-Hsien Li
- Department of Physics, National Central University, Zhongli, 32001, Taiwan.
| | - Chun-Ming Wu
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Chin-Wei Wang
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
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Yang Y, Wang WS, Ting CS, Wang QH. Monolayer NbF 4: a 4d 1-analogue of cuprates. Sci Bull (Beijing) 2020; 65:1901-1906. [PMID: 36738055 DOI: 10.1016/j.scib.2020.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 05/10/2020] [Accepted: 06/22/2020] [Indexed: 02/07/2023]
Abstract
The electronic structure and possible electronic orders in monolayer NbF4 are investigated by density functional theory and functional renormalization group. Because of the niobium-centered octahedra, the energy band near the Fermi level is found to derive from the 4dxy orbital, well separated from the other bands. Local Coulomb interaction drives the undoped system into an antiferromagnetic insulator. Upon suitable electron/hole doping, the system is found to develop [Formula: see text] -wave superconductivity with sizable transition temperature. Therefore, the monolayer NbF4 may be an exciting 4d1 analogue of cuprates, providing a new two-dimensional platform for high-Tc superconductivity.
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Affiliation(s)
- Yang Yang
- Texas Center for Superconductivity and Department of Physics, University of Houston, Houston TX77204, USA; College of Physics and Electronic Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, China
| | - Wan-Sheng Wang
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Chin-Sen Ting
- Texas Center for Superconductivity and Department of Physics, University of Houston, Houston TX77204, USA
| | - Qiang-Hua Wang
- National Laboratory of Solid State Microstructures & School of Physics, Nanjing University, Nanjing 210093, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
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Xin T, Li Y, Fan YA, Zhu X, Zhang Y, Nie X, Li J, Liu Q, Lu D. Quantum Phases of Three-Dimensional Chiral Topological Insulators on a Spin Quantum Simulator. PHYSICAL REVIEW LETTERS 2020; 125:090502. [PMID: 32915602 DOI: 10.1103/physrevlett.125.090502] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 07/07/2020] [Accepted: 08/04/2020] [Indexed: 05/22/2023]
Abstract
The detection of topological phases of matter has become a central issue in recent years. Conventionally, the realization of a specific topological phase in condensed matter physics relies on probing the underlying surface band dispersion or quantum transport signature of a real material, which may be imperfect or even absent. On the other hand, quantum simulation offers an alternative approach to directly measure the topological invariant on a universal quantum computer. However, experimentally demonstrating high-dimensional topological phases remains a challenge due to the technical limitations of current experimental platforms. Here, we investigate the three-dimensional topological insulators in the AIII (chiral unitary) symmetry class, which yet lack experimental realization. Using the nuclear magnetic resonance system, we experimentally demonstrate their topological properties, where a dynamical quenching approach is adopted and the dynamical bulk-boundary correspondence in the momentum space is observed. As a result, the topological invariants are measured with high precision on the band-inversion surface, exhibiting robustness to the decoherence effect. Our Letter paves the way toward the quantum simulation of topological phases of matter in higher dimensions and more complex systems through controllable quantum phases transitions.
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Affiliation(s)
- Tao Xin
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yishan Li
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yu-Ang Fan
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xuanran Zhu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yingjie Zhang
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xinfang Nie
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jun Li
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Qihang Liu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Dawei Lu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
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Rømer AT, Scherer DD, Eremin IM, Hirschfeld PJ, Andersen BM. Knight Shift and Leading Superconducting Instability from Spin Fluctuations in Sr_{2}RuO_{4}. PHYSICAL REVIEW LETTERS 2019; 123:247001. [PMID: 31922834 DOI: 10.1103/physrevlett.123.247001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Indexed: 06/10/2023]
Abstract
Recent nuclear magnetic resonance studies [A. Pustogow et al., Nature 574, 72 (2019)] have challenged the prevalent chiral triplet pairing scenario proposed for Sr_{2}RuO_{4}. To provide guidance from microscopic theory as to which other pair states might be compatible with the new data, we perform a detailed theoretical study of spin fluctuation mediated pairing for this compound. We map out the phase diagram as a function of spin-orbit coupling, interaction parameters, and band structure properties over physically reasonable ranges, comparing when possible with photoemission and inelastic neutron scattering data information. We find that even-parity pseudospin singlet solutions dominate large regions of the phase diagram, but in certain regimes spin-orbit coupling favors a near-nodal odd-parity triplet superconducting state, which is either helical or chiral depending on the proximity of the γ band to the van Hove points. A surprising near degeneracy of the nodal s^{'} and d_{x^{2}-y^{2}} wave solutions leads to the possibility of a near-nodal time-reversal symmetry broken s^{'}+id_{x^{2}-y^{2}} pair state. Predictions for the temperature dependence of the Knight shift for fields in and out of plane are presented for all states.
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Affiliation(s)
- A T Rømer
- Niels Bohr Institute, University of Copenhagen, Vibenhuset, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
- Institut Laue-Langevin, 71 avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - D D Scherer
- Niels Bohr Institute, University of Copenhagen, Vibenhuset, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
| | - I M Eremin
- Institut für Theoretische Physik III, Ruhr-Universität Bochum, D-44801 Bochum, Germany
- National University of Science and Technology MISiS, 119049 Moscow, Russia
| | - P J Hirschfeld
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, Vibenhuset, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
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