1
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Luo JJ, Pu H, Guan XW. Exact results of the one-dimensional repulsive Hubbard model. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:117601. [PMID: 39284352 DOI: 10.1088/1361-6633/ad7b70] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 09/16/2024] [Indexed: 09/20/2024]
Abstract
We present analytical results of the fundamental properties of the one-dimensional (1D) Hubbard model with a repulsive interaction. The new model results with arbitrary external fields include: (I) using the exact solutions of the Bethe ansatz equations of the Hubbard model, we first rigorously calculate the gapless spin and charge excitations, exhibiting exotic features of fractionalized spinons and holons. We then investigate the gapped excitations in terms of the spin string and thek-Λstring bound states at arbitrary driving fields, showing subtle differences in spin magnons and chargeη-pair excitations. (II) For a high-density and high spin magnetization region, i.e. near the quadruple critical point, we further analytically obtain the thermodynamic properties, dimensionless ratios and scaling functions near quantum phase transitions. (III) Importantly, we give the general scaling functions at quantum criticality for arbitrary filling and interaction strength. These can directly apply to other integrable models. (IV) Based on the fractional excitations and the scaling laws, the spin-incoherent Luttinger liquid (SILL) with only the charge propagation mode is elucidated by the asymptotic of the two-point correlation functions with the help of conformal field theory. We also, for the first time, obtain the analytical results of the thermodynamics for the SILL. (V) Finally, to capture deeper insights into the Mott insulator and interaction-driven criticality, we further study the double occupancy and propose its associated contact and contact susceptibilities, through which an adiabatic cooling scheme based upon quantum criticality is proposed. In this scenario, we build up general relations among arbitrary external- and internal-potential-driven quantum phase transitions, providing a comprehensive understanding of quantum criticality. Our methods offer rich perspectives of quantum integrability and offer promising guidance for future experiments with interacting electrons and ultracold atoms, both with and without a lattice.
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Affiliation(s)
- Jia-Jia Luo
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Han Pu
- Department of Physics and Astronomy, Rice University, Houston, TX 77251-1892, United States of America
| | - Xi-Wen Guan
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
- NSFC-SPTP Peng Huanwu Center for Fundamental Theory, Xi'an 710127, People's Republic of China
- Department of Fundamental and Theoretical Physics, Research School of Physics, Australian National University, Canberra ACT 0200, Australia
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2
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Ramos FB, Pereira RG, Eggert S, Schneider I. Nonlinear Effects on Charge Fractionalization in Critical Chains. PHYSICAL REVIEW LETTERS 2024; 133:086502. [PMID: 39241726 DOI: 10.1103/physrevlett.133.086502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Accepted: 07/16/2024] [Indexed: 09/09/2024]
Abstract
We investigate the generic transport in a one-dimensional strongly correlated fermionic chain beyond linear response. Starting from a Gaussian wave packet with positive momentum on top of the ground state, we find that the numerical time evolution splits the signal into at least three distinct fractional charges moving with different velocities. A fractional left-moving charge is expected from conventional Luttinger liquid theory, but for the prediction of the two separate right-moving packets the nonlinearity of the dispersion must also be taken into account. This out-of-equilibrium protocol therefore allows a direct measurement of nonlinear interaction parameters, which also govern threshold singularities of dynamic response functions. The nonlinear Luttinger liquid theory also predicts the correct dynamics at low energies, where it agrees with the conventional Luttinger liquid. Moreover, at high energies, the wave packet dynamics reveals signatures of composite excitations containing two-particle bound states. Our results uncover a simple strategy to probe the nonlinear regime in time-resolved experiments in quantum wires and ultracold-atom platforms.
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3
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Yu G, Wang P, Uzan-Narovlansky AJ, Jia Y, Onyszczak M, Singha R, Gui X, Song T, Tang Y, Watanabe K, Taniguchi T, Cava RJ, Schoop LM, Wu S. Evidence for two dimensional anisotropic Luttinger liquids at millikelvin temperatures. Nat Commun 2023; 14:7025. [PMID: 37919261 PMCID: PMC10622557 DOI: 10.1038/s41467-023-42821-2] [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: 03/03/2023] [Accepted: 10/23/2023] [Indexed: 11/04/2023] Open
Abstract
Interacting electrons in one dimension (1D) are governed by the Luttinger liquid (LL) theory in which excitations are fractionalized. Can a LL-like state emerge in a 2D system as a stable zero-temperature phase? This question is crucial in the study of non-Fermi liquids. A recent experiment identified twisted bilayer tungsten ditelluride (tWTe2) as a 2D host of LL-like physics at a few kelvins. Here we report evidence for a 2D anisotropic LL state down to 50 mK, spontaneously formed in tWTe2 with a twist angle of ~ 3o. While the system is metallic-like and nearly isotropic above 2 K, a dramatically enhanced electronic anisotropy develops in the millikelvin regime. In the anisotropic phase, we observe characteristics of a 2D LL phase including a power-law across-wire conductance and a zero-bias dip in the along-wire differential resistance. Our results represent a step forward in the search for stable LL physics beyond 1D.
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Affiliation(s)
- Guo Yu
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Pengjie Wang
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | | | - Yanyu Jia
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Michael Onyszczak
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Ratnadwip Singha
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Xin Gui
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Tiancheng Song
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Yue Tang
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Robert J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Leslie M Schoop
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Sanfeng Wu
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
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4
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Cavazos-Cavazos D, Senaratne R, Kafle A, Hulet RG. Thermal disruption of a Luttinger liquid. Nat Commun 2023; 14:3154. [PMID: 37258570 DOI: 10.1038/s41467-023-38767-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 05/15/2023] [Indexed: 06/02/2023] Open
Abstract
The Tomonaga-Luttinger liquid (TLL) theory describes the low-energy excitations of strongly correlated one-dimensional (1D) fermions. In the past years, a number of studies have provided a detailed understanding of this universality class. More recently, theoretical investigations that go beyond the standard low-temperature, linear-response TLL regime have been developed. While these provide a basis for understanding the dynamics of the spin-incoherent Luttinger liquid, there are few experimental investigations in this regime. Here we report the observation of a thermally induced, spin-incoherent Luttinger liquid in a 6Li atomic Fermi gas confined to 1D. We use Bragg spectroscopy to measure the suppression of spin-charge separation and the decay of correlations as the temperature is increased. Our results probe the crossover between the coherent and incoherent regimes of the Luttinger liquid and elucidate the roles of the charge and the spin degrees of freedom in this regime.
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Affiliation(s)
| | - Ruwan Senaratne
- Department of Physics and Astronomy, Rice University, Houston, Texas, 77005, USA
| | - Aashish Kafle
- Department of Physics and Astronomy, Rice University, Houston, Texas, 77005, USA
| | - Randall G Hulet
- Department of Physics and Astronomy, Rice University, Houston, Texas, 77005, USA.
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5
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Guan XW, He P. New trends in quantum integrability: recent experiments with ultracold atoms. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:114001. [PMID: 36170807 DOI: 10.1088/1361-6633/ac95a9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/28/2022] [Indexed: 06/16/2023]
Abstract
Over the past two decades quantum engineering has made significant advances in our ability to create genuine quantum many-body systems using ultracold atoms. In particular, some prototypical exactly solvable Yang-Baxter systems have been successfully realized allowing us to confront elegant and sophisticated exact solutions of these systems with their experimental counterparts. The new experimental developments show a variety of fundamental one-dimensional (1D) phenomena, ranging from the generalized hydrodynamics to dynamical fermionization, Tomonaga-Luttinger liquids, collective excitations, fractional exclusion statistics, quantum holonomy, spin-charge separation, competing orders with high spin symmetry and quantum impurity problems. This article briefly reviews these developments and provides rigorous understanding of those observed phenomena based on the exact solutions while highlighting the uniqueness of 1D quantum physics. The precision of atomic physics realizations of integrable many-body problems continues to inspire significant developments in mathematics and physics while at the same time offering the prospect to contribute to future quantum technology.
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Affiliation(s)
- Xi-Wen Guan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
- NSFC-SPTP Peng Huanwu Center for Fundamental Theory, Xi'an 710127, People's Republic of China
- Department of Fundamental and Theoretical Physics, Research School of Physics, Australian National University, Canberra ACT 0200, Australia
| | - Peng He
- Bureau of Frontier Sciences and Education, Chinese Academy of Sciences, Beijing 100864,People's Republic of China
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6
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Zhu T, Ruan W, Wang YQ, Tsai HZ, Wang S, Zhang C, Wang T, Liou F, Watanabe K, Taniguchi T, Neaton JB, Weber-Bargioni A, Zettl A, Qiu ZQ, Zhang G, Wang F, Moore JE, Crommie MF. Imaging gate-tunable Tomonaga-Luttinger liquids in 1H-MoSe 2 mirror twin boundaries. NATURE MATERIALS 2022; 21:748-753. [PMID: 35710632 DOI: 10.1038/s41563-022-01277-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 04/25/2022] [Indexed: 06/15/2023]
Abstract
One-dimensional electron systems exhibit fundamentally different properties than higher-dimensional systems. For example, electron-electron interactions in one-dimensional electron systems have been predicted to induce Tomonaga-Luttinger liquid behaviour. Naturally occurring grain boundaries in single-layer transition metal dichalcogenides exhibit one-dimensional conducting channels that have been proposed to host Tomonaga-Luttinger liquids, but charge density wave physics has also been suggested to explain their behaviour. Clear identification of the electronic ground state of this system has been hampered by an inability to electrostatically gate such boundaries and tune their charge carrier concentration. Here we present a scanning tunnelling microscopy and spectroscopy study of gate-tunable mirror twin boundaries in single-layer 1H-MoSe2 devices. Gating enables scanning tunnelling microscopy and spectroscopy for different mirror twin boundary electron densities, thus allowing precise characterization of electron-electron interaction effects. Visualization of the resulting mirror twin boundary electronic structure allows unambiguous identification of collective density wave excitations having two velocities, in quantitative agreement with the spin-charge separation predicted by finite-length Tomonaga-Luttinger liquid theory.
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Affiliation(s)
- Tiancong Zhu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Wei Ruan
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Physics, University of California, Berkeley, CA, USA.
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China.
| | - Yan-Qi Wang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Hsin-Zon Tsai
- Department of Physics, University of California, Berkeley, CA, USA
| | - Shuopei Wang
- Beijing National Laboratory for Condensed Matter Physics, Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, China
| | - Canxun Zhang
- Department of Physics, University of California, Berkeley, CA, USA
- Kavli Energy Nano Sciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Tianye Wang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Franklin Liou
- Department of Physics, University of California, Berkeley, CA, USA
- Kavli Energy Nano Sciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Jeffrey B Neaton
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Alexander Weber-Bargioni
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Alex Zettl
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
- Kavli Energy Nano Sciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Z Q Qiu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Guangyu Zhang
- Beijing National Laboratory for Condensed Matter Physics, Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Feng Wang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Physics, University of California, Berkeley, CA, USA.
- Kavli Energy Nano Sciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Joel E Moore
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Physics, University of California, Berkeley, CA, USA.
- Kavli Energy Nano Sciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Michael F Crommie
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Physics, University of California, Berkeley, CA, USA.
- Kavli Energy Nano Sciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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7
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Senaratne R, Cavazos-Cavazos D, Wang S, He F, Chang YT, Kafle A, Pu H, Guan XW, Hulet RG. Spin-charge separation in a one-dimensional Fermi gas with tunable interactions. Science 2022; 376:1305-1308. [PMID: 35709259 DOI: 10.1126/science.abn1719] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Ultracold atoms confined to periodic potentials have proven to be a powerful tool for quantum simulation of complex many-body systems. We confine fermions to one dimension to realize the Tomonaga-Luttinger liquid model, which describes the highly collective nature of their low-energy excitations. We use Bragg spectroscopy to directly excite either the spin or charge waves for various strengths of repulsive interaction. We observe that the velocity of the spin and charge excitations shift in opposite directions with increasing interaction, a hallmark of spin-charge separation. The excitation spectra are in quantitative agreement with the exact solution of the Yang-Gaudin model and the Tomonaga-Luttinger liquid theory. Furthermore, we identify effects of nonlinear corrections to this theory that arise from band curvature and back-scattering.
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Affiliation(s)
- Ruwan Senaratne
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
| | | | - Sheng Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Feng He
- University of Chinese Academy of Sciences, Beijing 100049, China.,International School for Advanced Studies (SISSA) and National Institute of Nuclear Physics (INFN), Sezione di Trieste, 34136 Trieste, Italy
| | - Ya-Ting Chang
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
| | - Aashish Kafle
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
| | - Han Pu
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
| | - Xi-Wen Guan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,Department of Theoretical Physics, RSPE, Australian National University, Canberra, ACT 0200, Australia
| | - Randall G Hulet
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA
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8
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Vianez PMT, Jin Y, Moreno M, Anirban AS, Anthore A, Tan WK, Griffiths JP, Farrer I, Ritchie DA, Schofield AJ, Tsyplyatyev O, Ford CJB. Observing separate spin and charge Fermi seas in a strongly correlated one-dimensional conductor. SCIENCE ADVANCES 2022; 8:eabm2781. [PMID: 35714181 PMCID: PMC9205598 DOI: 10.1126/sciadv.abm2781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
An electron is usually considered to have only one form of kinetic energy, but could it have more, for its spin and charge, by exciting other electrons? In one dimension (1D), the physics of interacting electrons is captured well at low energies by the Tomonaga-Luttinger model, yet little has been observed experimentally beyond this linear regime. Here, we report on measurements of many-body modes in 1D gated wires using tunneling spectroscopy. We observe two parabolic dispersions, indicative of separate Fermi seas at high energies, associated with spin and charge excitations, together with the emergence of two additional 1D "replica" modes that strengthen with decreasing wire length. The interaction strength is varied by changing the amount of 1D intersubband screening by more than 45%. Our findings not only demonstrate the existence of spin-charge separation in the whole energy band outside the low-energy limit of the Tomonaga-Luttinger model but also set a constraint on the validity of the newer nonlinear Tomonaga-Luttinger theory.
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Affiliation(s)
- Pedro M. T. Vianez
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Yiqing Jin
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - María Moreno
- Departamento de Física Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca, Spain
| | - Ankita S. Anirban
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Anne Anthore
- Université de Paris, C2N, 91120 Palaiseau, France
| | - Wooi Kiat Tan
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Jonathan P. Griffiths
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Ian Farrer
- Department of Electronic and Electrical Engineering, University of Sheffield, 3 Solly Street, Sheffield S1 4DE, UK
| | - David A. Ritchie
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
- Department of Physics, Swansea University, Vivian Tower, Singleton Park, Swansea SA2 8PP, UK
| | | | - Oleksandr Tsyplyatyev
- Institut für Theoretische Physik, Universität Frankfurt, Max-von-Laue Straße 1, 60438 Frankfurt, Germany
| | - Christopher J. B. Ford
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
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9
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One-dimensional Luttinger liquids in a two-dimensional moiré lattice. Nature 2022; 605:57-62. [PMID: 35508779 DOI: 10.1038/s41586-022-04514-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 02/03/2022] [Indexed: 11/08/2022]
Abstract
The Luttinger liquid (LL) model of one-dimensional (1D) electronic systems provides a powerful tool for understanding strongly correlated physics, including phenomena such as spin-charge separation1. Substantial theoretical efforts have attempted to extend the LL phenomenology to two dimensions, especially in models of closely packed arrays of 1D quantum wires2-13, each being described as a LL. Such coupled-wire models have been successfully used to construct two-dimensional (2D) anisotropic non-Fermi liquids2-6, quantum Hall states7-9, topological phases10,11 and quantum spin liquids12,13. However, an experimental demonstration of high-quality arrays of 1D LLs suitable for realizing these models remains absent. Here we report the experimental realization of 2D arrays of 1D LLs with crystalline quality in a moiré superlattice made of twisted bilayer tungsten ditelluride (tWTe2). Originating from the anisotropic lattice of the monolayer, the moiré pattern of tWTe2 hosts identical, parallel 1D electronic channels, separated by a fixed nanoscale distance, which is tuneable by the interlayer twist angle. At a twist angle of approximately 5 degrees, we find that hole-doped tWTe2 exhibits exceptionally large transport anisotropy with a resistance ratio of around 1,000 between two orthogonal in-plane directions. The across-wire conductance exhibits power-law scaling behaviours, consistent with the formation of a 2D anisotropic phase that resembles an array of LLs. Our results open the door for realizing a variety of correlated and topological quantum phases based on coupled-wire models and LL physics.
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10
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Yakimenko II, Yakimenko IP. Electronic properties of semiconductor quantum wires for shallow symmetric and asymmetric confinements. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:105302. [PMID: 34852329 DOI: 10.1088/1361-648x/ac3f01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 12/01/2021] [Indexed: 06/13/2023]
Abstract
Quantum wires (QWs) and quantum point contacts (QPCs) have been realized in GaAs/AlGaAs heterostructures in which a two-dimensional electron gas resides at the interface between GaAs and AlGaAs layered semiconductors. The electron transport in these structures has previously been studied experimentally and theoretically, and a 0.7 conductance anomaly has been discovered. The present paper is motivated by experiments with a QW in shallow symmetric and asymmetric confinements that have shown additional conductance anomalies at zero magnetic field. The proposed device consists of a QPC that is formed by split gates and a top gate between two large electron reservoirs. This paper is focussed on the theoretical study of electron transport through a wide top-gated QPC in a low-density regime and is based on density functional theory. The electron-electron interaction and shallow confinement make the splitting of the conduction channel into two channels possible. Each of them becomes spin-polarized at certain split and top gates voltages and may contribute to conductance giving rise to additional conductance anomalies. For symmetrically loaded split gates two conduction channels contribute equally to conductance. For the case of asymmetrically applied voltage between split gates conductance anomalies may occur between values of 0.25(2e2/h) and 0.7(2e2/h) depending on the increased asymmetry in split gates voltages. This corresponds to different degrees of spin-polarization in the two conduction channels that contribute differently to conductance. In the case of a strong asymmetry in split gates voltages one channel of conduction is pinched off and just the one remaining channel contributes to conductance. We have found that on the perimeter of the anti-dot there are spin-polarized states. These states may also contribute to conductance if the radius of the anti-dot is small enough and tunneling between these states may occur. The spin-polarized states in the QPC with shallow confinement tuned by electric means may be used for the purposes of quantum technology.
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Affiliation(s)
- Irina I Yakimenko
- Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
| | - Ivan P Yakimenko
- Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
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11
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Gate induced quantum wires in GaAs/AlGaAs heterostructures by cleaved edge deposition. Sci Rep 2021; 11:21736. [PMID: 34741080 PMCID: PMC8571278 DOI: 10.1038/s41598-021-01130-8] [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: 07/16/2021] [Accepted: 10/22/2021] [Indexed: 11/17/2022] Open
Abstract
Electric conductors with dimensions reduced to the nanometer scale are the prerequisite of the quantum devices upon which the future advanced electronics is expected to be based. In the past, the fabrication of one-dimensional (1D) wires has been a particular challenge because they have to be defect-free over their whole length, which can be several tens µm. Excellent 1D wires have been produced by cleaving semiconductors (GaAs, AlGaAs) in ultra high vacuum and overgrowing the pristine edge surface by molecular beam epitaxy (MBE)1,2. Unfortunately, this cleaved edge overgrowth (CEO) technique did not find wide-spread use because it requires a series of elaborate steps that are difficult to accomplish. In this Letter, we present a greatly simplified variation of this technique where the cleaving takes place in ambient air and the MBE overgrowth is replaced by a standard deposition process. Wires produced by this cleaved edge deposition (CED) technique have properties that are as least as good as the traditional CEO ones. Due to its simplicity, the CED technique offers a generally accessible way to produce 1D devices.
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12
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De Daniloff C, Tharrault M, Enesa C, Salomon C, Chevy F, Reimann T, Struck J. In Situ Thermometry of Fermionic Cold-Atom Quantum Wires. PHYSICAL REVIEW LETTERS 2021; 127:113602. [PMID: 34558929 DOI: 10.1103/physrevlett.127.113602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
We study ensembles of fermionic cold-atom quantum wires with tunable transverse mode population and single-wire resolution. From in situ density profiles, we determine the temperature of the atomic wires in the weakly interacting limit and reconstruct the underlying potential landscape. By varying atom number and temperature, we control the occupation of the transverse modes and study the 1D-3D crossover. In the 1D limit, we observe an increase of the reduced temperature T/T_{F} at nearly constant entropy per particle S/Nk_{B}. The ability to probe individual atomic wires in situ paves the way to quantitatively study equilibrium and transport properties of strongly interacting 1D Fermi gases.
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Affiliation(s)
- Clément De Daniloff
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Marin Tharrault
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Cédric Enesa
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Christophe Salomon
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Frédéric Chevy
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Thomas Reimann
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Julian Struck
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
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13
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Kwapiński T, Kurzyna M. Topological Atomic Chains on 2D Hybrid Structure. MATERIALS 2021; 14:ma14123289. [PMID: 34198678 PMCID: PMC8232186 DOI: 10.3390/ma14123289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/01/2021] [Accepted: 06/10/2021] [Indexed: 11/16/2022]
Abstract
Mid-gap 1D topological states and their electronic properties on different 2D hybrid structures are investigated using the tight binding Hamiltonian and the Green's function technique. There are considered straight armchair-edge and zig-zag Su-Schrieffer-Heeger (SSH) chains coupled with real 2D electrodes which density of states (DOS) are characterized by the van Hove singularities. In this work, it is shown that such 2D substrates substantially influence topological states end evoke strong asymmetry in their on-site energetic structures, as well as essential modifications of the spectral density function (local DOS) along the chain. In the presence of the surface singularities the SSH topological state is split, or it is strongly localized and becomes dispersionless (tends to the atomic limit). Additionally, in the vicinity of the surface DOS edges this state is asymmetrical and consists of a wide bulk part together with a sharp localized peak in its local DOS structure. Different zig-zag and armachair-edge configurations of the chain show the spatial asymmetry in the chain local DOS; thus, topological edge states at both chain ends can appear for different energies. These new effects cannot be observed for ideal wide band limit electrodes but they concern 1D topological states coupled with real 2D hybrid structures.
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14
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Hudson KL, Srinivasan A, Goulko O, Adam J, Wang Q, Yeoh LA, Klochan O, Farrer I, Ritchie DA, Ludwig A, Wieck AD, von Delft J, Hamilton AR. New signatures of the spin gap in quantum point contacts. Nat Commun 2021; 12:5. [PMID: 33397919 PMCID: PMC7782751 DOI: 10.1038/s41467-020-19895-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/12/2020] [Indexed: 11/09/2022] Open
Abstract
One dimensional semiconductor systems with strong spin-orbit interaction are both of fundamental interest and have potential applications to topological quantum computing. Applying a magnetic field can open a spin gap, a pre-requisite for Majorana zero modes. The spin gap is predicted to manifest as a field dependent dip on the first 1D conductance plateau. However, disorder and interaction effects make identifying spin gap signatures challenging. Here we study experimentally and numerically the 1D channel in a series of low disorder p-type GaAs quantum point contacts, where spin-orbit and hole-hole interactions are strong. We demonstrate an alternative signature for probing spin gaps, which is insensitive to disorder, based on the linear and non-linear response to the orientation of the applied magnetic field, and extract a spin-orbit gap ΔE ≈ 500 μeV. This approach could enable one-dimensional hole systems to be developed as a scalable and reproducible platform for topological quantum applications. In one-dimensional systems, the combination of a strong spin-orbit interaction and an applied magnetic field can give rise to a spin-gap, however experimental identification is difficult. Here, the authors present new signatures for the spin-gap, and verify these experimentally in hole QPCs.
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Affiliation(s)
- K L Hudson
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia.,ARC Centre of Excellence in Future Low-Energy Electronics Technologies, University of New South Wales, Sydney, NSW, 2052, Australia
| | - A Srinivasan
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia.,ARC Centre of Excellence in Future Low-Energy Electronics Technologies, University of New South Wales, Sydney, NSW, 2052, Australia
| | - O Goulko
- Department of Physics, University of Massachusetts, Boston, MA, 02125, USA
| | - J Adam
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Q Wang
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia.,ARC Centre of Excellence in Future Low-Energy Electronics Technologies, University of New South Wales, Sydney, NSW, 2052, Australia
| | - L A Yeoh
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia
| | - O Klochan
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia.,ARC Centre of Excellence in Future Low-Energy Electronics Technologies, University of New South Wales, Sydney, NSW, 2052, Australia
| | - I Farrer
- Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, UK
| | - D A Ritchie
- Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - A Ludwig
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780, Bochum, Germany
| | - A D Wieck
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780, Bochum, Germany
| | - J von Delft
- Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians Universität, München, Theresienstrasse 37, D-80333, München, Germany
| | - A R Hamilton
- School of Physics, University of New South Wales, Sydney, NSW, 2052, Australia. .,ARC Centre of Excellence in Future Low-Energy Electronics Technologies, University of New South Wales, Sydney, NSW, 2052, Australia.
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15
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Gao H, Coulthard JR, Jaksch D, Mur-Petit J. Anomalous Spin-Charge Separation in a Driven Hubbard System. PHYSICAL REVIEW LETTERS 2020; 125:195301. [PMID: 33216562 DOI: 10.1103/physrevlett.125.195301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 10/05/2020] [Indexed: 06/11/2023]
Abstract
Spin-charge separation (SCS) is a striking manifestation of strong correlations in low-dimensional quantum systems, whereby a fermion splits into separate spin and charge excitations that travel at different speeds. Here, we demonstrate that periodic driving enables control over SCS in a Hubbard system near half filling. In one dimension, we predict analytically an exotic regime where charge travels slower than spin and can even become "frozen," in agreement with numerical calculations. In two dimensions, the driving slows both charge and spin and leads to complex interferences between single-particle and pair-hopping processes.
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Affiliation(s)
- Hongmin Gao
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Jonathan R Coulthard
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Dieter Jaksch
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore
| | - Jordi Mur-Petit
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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16
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He F, Jiang YZ, Lin HQ, Hulet RG, Pu H, Guan XW. Emergence and Disruption of Spin-Charge Separation in One-Dimensional Repulsive Fermions. PHYSICAL REVIEW LETTERS 2020; 125:190401. [PMID: 33216574 DOI: 10.1103/physrevlett.125.190401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/17/2020] [Indexed: 06/11/2023]
Abstract
At low temperature, collective excitations of one-dimensional (1D) interacting fermions exhibit spin-charge separation, a unique feature predicted by the Tomonaga-Luttinger liquid (TLL) theory, but a rigorous understanding remains challenging. Using the thermodynamic Bethe ansatz (TBA) formalism, we analytically derive universal properties of a 1D repulsive spin-1/2 Fermi gas with arbitrary interaction strength. We show how spin-charge separation emerges from the exact TBA formalism, and how it is disrupted by the interplay between the two degrees of freedom that brings us beyond the TLL paradigm. Based on the exact low-lying excitation spectra, we further evaluate the spin and charge dynamical structure factors (DSFs). The peaks of the DSFs exhibit distinguishable propagating velocities of spin and charge as functions of interaction strength, which can be observed by Bragg spectroscopy with ultracold atoms.
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Affiliation(s)
- Feng He
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu-Zhu Jiang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
| | - Hai-Qing Lin
- Beijing Computational Science Research Center, Beijing 100193, China
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Randall G Hulet
- Department of Physics and Astronomy, and Rice Center for Quantum Materials, Rice University, Houston, Texas 77251-1892, USA
| | - Han Pu
- Department of Physics and Astronomy, and Rice Center for Quantum Materials, Rice University, Houston, Texas 77251-1892, USA
| | - Xi-Wen Guan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China
- Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
- Department of Theoretical Physics, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200, Australia
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17
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Xia Y, Zhang J, Jin Y, Ho W, Xu H, Xie M. Charge Density Modulation and the Luttinger Liquid State in MoSe 2 Mirror Twin Boundaries. ACS NANO 2020; 14:10716-10722. [PMID: 32806039 DOI: 10.1021/acsnano.0c05397] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A mirror twin-domain boundary (MTB) in monolayer MoSe2 represents a (quasi) one-dimensional metallic system. Its electronic properties, particularly the low-energy excitations in the so-called 4|4P-type MTB, have drawn considerable research attention. Reports of quantum well states, charge density waves, and the Tomonaga-Luttinger liquid (TLL) have all been made. Here, by controlling the lengths of the MTBs and employing different substrates, we reveal by low-temperature scanning tunneling microscopy/spectroscopy, Friedel oscillations and quantum confinement effects causing the charge density modulations along the defect. The results are inconsistent with charge density waves. Interestingly, for graphene-supported samples, TLL in the MTBs is suggested, whereas that grown on gold, an ordinary Fermi liquid, is indicated.
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Affiliation(s)
- Yipu Xia
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Junqiu Zhang
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Yuanjun Jin
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Wingkin Ho
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Hu Xu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Maohai Xie
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
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18
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Kaur K, Sharma A, Garg V, Moudgil RK. Dynamic correlation effects on correlational properties of finite-temperature quasi-one-dimensional electron gas. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:335403. [PMID: 32289766 DOI: 10.1088/1361-648x/ab88f3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
We have studied correlational properties of quasi-one-dimensional electron gas at finite temperatureTby incorporating the dynamics of electron correlations within the quantum version of the self-consistent mean-field approach of Singwi, Tosi, Land, and Sjölander. Static structure factor, pair-correlation function, static density susceptibility, excess kinetic energy, and free correlation energy are calculated covering a wide range of temperature and electron number density. As at absolute zero temperature, the inclusion of dynamics of correlations results in stronger spatial electron correlations, with a pronounced peak in the static structure factor at wave vectorq∼ 3.5kF, which grows further with decreasing electron density. Below a critical density, the static density susceptibility seems to diverge at this value ofq, signaling a transition from liquid to the Wigner crystal state-a prediction in qualitative agreement with recent simulations and experiment. However, thermal effects tend to impede crystallization with the consequence that the critical density decreases significantly with risingT. On the other hand, the pair-correlation function at short range exhibits a non-monotonic dependence onT, initially becoming somewhat stronger with risingTand then weakening continuously above a sufficiently highT. The calculated free correlation energy shows a noticeable dependence onT, with its magnitude increasing with increase inT. Further, we have looked into the effect of temperature on the frequency-dependence of dynamic local-field correction factor and the plasmon dispersion. It is found that with risingTthe dynamics of correlations weakens, and the plasmon frequency exhibits a blue shift. Wherever interesting, we have compared our results with the lower-order approximate calculations and zero-Tquantum Monte Carlo simulations.
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Affiliation(s)
- Kulveer Kaur
- Department of Physics, Punjabi University, Patiala - 147 002, India
| | - Akariti Sharma
- Department of Physics, Punjabi University, Patiala - 147 002, India
| | - Vinayak Garg
- Department of Physics, Punjabi University, Patiala - 147 002, India
| | - R K Moudgil
- Department of Physics, Kurukshetra University, Kurukshetra - 136 119, India
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19
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Xia Y, Wang B, Zhang J, Jin Y, Tian H, Ho W, Xu H, Jin C, Xie M. Quantum Confined Tomonaga-Luttinger Liquid in Mo 6Se 6 Nanowires Converted from an Epitaxial MoSe 2 Monolayer. NANO LETTERS 2020; 20:2094-2099. [PMID: 32092277 DOI: 10.1021/acs.nanolett.0c00090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Confining interacting particles in one-dimension (1D) changes the electronic behavior of the system fundamentally, which has been studied extensively in the past. Examples of 1D metallic systems include carbon nanotubes, quasi-1D organic conductors, metal chains, and domain boundary defects in monolayer thick transition-metal dichalcogenides such as MoSe2. Here single and bundles of Mo6Se6 nanowires were fabricated through annealing a MoSe2 monolayer grown by molecular-beam epitaxy on graphene. Conversion from two-dimensional (2D) MoSe2 film to 1D Mo6Se6 nanowire is reversible. Mo6Se6 nanowires form preferentially at the Se-terminated zigzag edges of MoSe2 and stitch to it via two distinct atomic configurations. The Mo6Se6 wire is metallic and its length is tunable, which represents one of few 1D systems that exhibit properties pertinent to quantum confined Tomonaga-Luttinger liquid, as evidenced by scanning tunneling microscopic and spectroscopic studies.
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Affiliation(s)
- Yipu Xia
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Bo Wang
- State Key Laboratory of Silicon Materials, School of Materials and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Junqiu Zhang
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Yuanjun Jin
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Hao Tian
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Wingkin Ho
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Hu Xu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Chuanhong Jin
- State Key Laboratory of Silicon Materials, School of Materials and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Maohai Xie
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
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20
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Vijayan J, Sompet P, Salomon G, Koepsell J, Hirthe S, Bohrdt A, Grusdt F, Bloch I, Gross C. Time-resolved observation of spin-charge deconfinement in fermionic Hubbard chains. Science 2020; 367:186-189. [DOI: 10.1126/science.aay2354] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/14/2019] [Indexed: 11/02/2022]
Abstract
Elementary particles carry several quantum numbers, such as charge and spin. However, in an ensemble of strongly interacting particles, the emerging degrees of freedom can fundamentally differ from those of the individual constituents. For example, one-dimensional systems are described by independent quasiparticles carrying either spin (spinon) or charge (holon). Here, we report on the dynamical deconfinement of spin and charge excitations in real space after the removal of a particle in Fermi-Hubbard chains of ultracold atoms. Using space- and time-resolved quantum gas microscopy, we tracked the evolution of the excitations through their signatures in spin and charge correlations. By evaluating multipoint correlators, we quantified the spatial separation of the excitations in the context of fractionalization into single spinons and holons at finite temperatures.
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Affiliation(s)
- Jayadev Vijayan
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
| | - Pimonpan Sompet
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
| | - Guillaume Salomon
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
| | - Joannis Koepsell
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
| | - Sarah Hirthe
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
| | - Annabelle Bohrdt
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
- Department of Physics and Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany
| | - Fabian Grusdt
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
- Department of Physics and Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany
- Department of Physics and Arnold Sommerfeld Center for Theoretical Physics (ASC), Ludwig-Maximilians-Universität, Theresienstraße 37, 80333 München, Germany
| | - Immanuel Bloch
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
- Fakultät für Physik, Ludwig-Maximilians-Universität, Schellingstraße 4, 80799 München, Germany
| | - Christian Gross
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
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21
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Acciai M, Calzona A, Carrega M, Sassetti M. Spectral features of voltage pulses in interacting helical channels. EPJ WEB OF CONFERENCES 2020. [DOI: 10.1051/epjconf/202023000009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the interplay of voltage-driven excitations and electron-electron interactions in a pair of counterpropagating helical channels capacitively coupled to a time-dependent gate. By focusing on the non-equilibrium spectral properties of the system, we show how the spectral function is modified by external drives with different time profile in presence of Coulomb interactions. In particular, we focus on a Lorentzian drive and a square single pulse. In presence of strong enough electron-electron interactions, we find that both drives can result in minimal excitations, i.e. characterized by an excess spectral function with a definite sign. This is in contrast with what happens in the non-interacting case, where only properly quantized Lorentzian pulses are able to produce minimal excitations.
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22
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Barfknecht RE, Foerster A, Zinner NT. Dynamics of spin and density fluctuations in strongly interacting few-body systems. Sci Rep 2019; 9:15994. [PMID: 31690841 PMCID: PMC6831690 DOI: 10.1038/s41598-019-52392-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/15/2019] [Indexed: 11/09/2022] Open
Abstract
The decoupling of spin and density dynamics is a remarkable feature of quantum one-dimensional many-body systems. In a few-body regime, however, little is known about this phenomenon. To address this problem, we study the time evolution of a small system of strongly interacting fermions after a sudden change in the trapping geometry. We show that, even at the few-body level, the excitation spectrum of this system presents separate signatures of spin and density dynamics. Moreover, we describe the effect of considering additional internal states with SU(N) symmetry, which ultimately leads to the vanishing of spin excitations in a completely balanced system.
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Affiliation(s)
- Rafael Emilio Barfknecht
- Instituto de Física da UFRGS, Av. Bento Gonçalves, 9500, Porto Alegre, RS, Brazil.
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus, Denmark.
| | - Angela Foerster
- Instituto de Física da UFRGS, Av. Bento Gonçalves, 9500, Porto Alegre, RS, Brazil
| | - Nikolaj Thomas Zinner
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, DK-8000, Aarhus, Denmark
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23
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Schmidt TL, Dolcetto G, Pedder CJ, Le Hur K, Orth PP. Mechanical Resonances of Mobile Impurities in a One-Dimensional Quantum Fluid. PHYSICAL REVIEW LETTERS 2019; 123:075302. [PMID: 31491113 DOI: 10.1103/physrevlett.123.075302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Indexed: 06/10/2023]
Abstract
We study a one-dimensional interacting quantum liquid hosting a pair of mobile impurities causing backscattering. We determine the effective retarded interaction between the two impurities mediated by the liquid. We show that for strong backscattering this interaction gives rise to resonances and antiresonances in the finite-frequency mobility of the impurity pair. At the antiresonances, the two impurities remain at rest even when driven by a (small) external force. At the resonances, their synchronous motion follows the external drive in phase and reaches maximum amplitude. Using a perturbative renormalization group analysis in quantum tunneling across the impurities, we study the range of validity of our model. We predict that these mechanical antiresonances are observable in experiments on ultracold atom gases confined to one dimension.
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Affiliation(s)
- Thomas L Schmidt
- Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg
| | - Giacomo Dolcetto
- Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg
| | - Christopher J Pedder
- Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg
| | - Karyn Le Hur
- CPHT, CNRS, Institut Polytechnique de Paris, Route de Saclay, 91128 Palaiseau, France
| | - Peter P Orth
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
- Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA
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24
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Štrkalj A, Ferguson MS, Wolf TMR, Levkivskyi I, Zilberberg O. Tunneling into a Finite Luttinger Liquid Coupled to Noisy Capacitive Leads. PHYSICAL REVIEW LETTERS 2019; 122:126802. [PMID: 30978091 DOI: 10.1103/physrevlett.122.126802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/11/2019] [Indexed: 06/09/2023]
Abstract
Tunneling spectroscopy of one-dimensional interacting wires can be profoundly sensitive to the boundary conditions of the wire. Here, we analyze the tunneling spectroscopy of a wire coupled to capacitive metallic leads. Strikingly, with increasing many-body interactions in the wire, the impact of the boundary noise becomes more prominent. This interplay allows for a smooth crossover from standard 1D tunneling signatures into a regime where the tunneling is dominated by the fluctuations at the leads. This regime is characterized by an elevated zero-bias tunneling alongside a universal power-law decay at high energies. Furthermore, local tunneling measurements in this regime show a unique spatial dependence that marks the formation of plasmonic standing waves in the wire. Our result offers a tunable method by which to control the boundary effects and measure the interaction strength (Luttinger parameter) within the wire.
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Affiliation(s)
- Antonio Štrkalj
- Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Tobias M R Wolf
- Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Ivan Levkivskyi
- Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Oded Zilberberg
- Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland
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25
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Randeria MT, Agarwal K, Feldman BE, Ding H, Ji H, Cava RJ, Sondhi SL, Parameswaran SA, Yazdani A. Interacting multi-channel topological boundary modes in a quantum Hall valley system. Nature 2019; 566:363-367. [PMID: 30728501 DOI: 10.1038/s41586-019-0913-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 11/23/2018] [Indexed: 11/09/2022]
Abstract
Symmetry and topology are central to understanding quantum Hall ferromagnets (QHFMs), two-dimensional electronic phases with spontaneously broken spin or pseudospin symmetry whose wavefunctions also have topological properties1,2. Domain walls between distinct broken-symmetry QHFM phases are predicted to host gapless one-dimensional modes-that is, quantum channels that emerge because of a topological change in the underlying electronic wavefunctions at such interfaces. Although various QHFMs have been identified in different materials3-8, interacting electronic modes at these domain walls have not been probed. Here we use a scanning tunnelling microscope to directly visualize the spontaneous formation of boundary modes at domain walls between QHFM phases with different valley polarization (that is, the occupation of equal-energy but quantum mechanically distinct valleys in the electronic structure) on the surface of bismuth. Spectroscopy shows that these modes occur within a topological energy gap, which closes and reopens as the valley polarization switches across the domain wall. By changing the valley flavour and the number of modes at the domain wall, we can realize different regimes in which the valley-polarized channels are either metallic or develop a spectroscopic gap. This behaviour is a consequence of Coulomb interactions constrained by the valley flavour, which determines whether electrons in the topological modes can backscatter, making these channels a unique class of interacting one-dimensional quantum wires. QHFM domain walls can be realized in different classes of two-dimensional materials, providing the opportunity to explore a rich phase space of interactions in these quantum wires.
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Affiliation(s)
- Mallika T Randeria
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA
| | - Kartiek Agarwal
- Department of Electrical Engineering, Princeton University, Princeton, NJ, USA
| | - Benjamin E Feldman
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA.,Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, USA.,Department of Physics, Stanford University, Stanford, CA, USA
| | - Hao Ding
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA
| | - Huiwen Ji
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - S L Sondhi
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA
| | | | - Ali Yazdani
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, USA.
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26
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Nichols MA, Cheuk LW, Okan M, Hartke TR, Mendez E, Senthil T, Khatami E, Zhang H, Zwierlein MW. Spin transport in a Mott insulator of ultracold fermions. Science 2018; 363:383-387. [DOI: 10.1126/science.aat4387] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 11/20/2018] [Indexed: 11/02/2022]
Abstract
Strongly correlated materials are expected to feature unconventional transport properties, such that charge, spin, and heat conduction are potentially independent probes of the dynamics. In contrast to charge transport, the measurement of spin transport in such materials is highly challenging. We observed spin conduction and diffusion in a system of ultracold fermionic atoms that realizes the half-filled Fermi-Hubbard model. For strong interactions, spin diffusion is driven by super-exchange and doublon-hole–assisted tunneling, and strongly violates the quantum limit of charge diffusion. The technique developed in this work can be extended to finite doping, which can shed light on the complex interplay between spin and charge in the Hubbard model.
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27
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Avraham N, Reiner J, Kumar-Nayak A, Morali N, Batabyal R, Yan B, Beidenkopf H. Quasiparticle Interference Studies of Quantum Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707628. [PMID: 29862584 DOI: 10.1002/adma.201707628] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/13/2018] [Indexed: 06/08/2023]
Abstract
Exotic electronic states are realized in novel quantum materials. This field is revolutionized by the topological classification of materials. Such compounds necessarily host unique states on their boundaries. Scanning tunneling microscopy studies of these surface states have provided a wealth of spectroscopic characterization, with the successful cooperation of ab initio calculations. The method of quasiparticle interference imaging proves to be particularly useful for probing the dispersion relation of the surface bands. Herein, how a variety of additional fundamental electronic properties can be probed via this method is reviewed. It is demonstrated how quasiparticle interference measurements entail mesoscopic size quantization and the electronic phase coherence in semiconducting nanowires; helical spin protection and energy-momentum fluctuations in a topological insulator; and the structure of the Bloch wave function and the relative insusceptibility of topological electronic states to surface potential in a topological Weyl semimetal.
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Affiliation(s)
- Nurit Avraham
- Condensed Matter Department, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Jonathan Reiner
- Condensed Matter Department, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Abhay Kumar-Nayak
- Condensed Matter Department, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Noam Morali
- Condensed Matter Department, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Rajib Batabyal
- Condensed Matter Department, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Binghai Yan
- Condensed Matter Department, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Haim Beidenkopf
- Condensed Matter Department, Weizmann Institute of Science, Rehovot, 7610001, Israel
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28
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Patlatiuk T, Scheller CP, Hill D, Tserkovnyak Y, Barak G, Yacoby A, Pfeiffer LN, West KW, Zumbühl DM. Evolution of the quantum Hall bulk spectrum into chiral edge states. Nat Commun 2018; 9:3692. [PMID: 30209251 PMCID: PMC6135798 DOI: 10.1038/s41467-018-06025-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 08/13/2018] [Indexed: 11/30/2022] Open
Abstract
One of the most intriguing and fundamental properties of topological systems is the correspondence between the conducting edge states and the gapped bulk spectrum. Here, we use a GaAs cleaved edge quantum wire to perform momentum-resolved spectroscopy of the quantum Hall edge states in a tunnel-coupled 2D electron gas. This reveals the momentum and position of the edge states with unprecedented precision and shows the evolution from very low magnetic fields all the way to high fields where depopulation occurs. We present consistent analytical and numerical models, inferring the edge states from the well-known bulk spectrum, finding excellent agreement with the experiment-thus providing direct evidence for the bulk to edge correspondence. In addition, we observe various features beyond the single-particle picture, such as Fermi level pinning, exchange-enhanced spin splitting and signatures of edge-state reconstruction.
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Affiliation(s)
- T Patlatiuk
- Departement Physik, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - C P Scheller
- Departement Physik, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - D Hill
- Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
| | - Y Tserkovnyak
- Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
| | - G Barak
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - A Yacoby
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - L N Pfeiffer
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - K W West
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - D M Zumbühl
- Departement Physik, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
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29
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Yang TL, Grišins P, Chang YT, Zhao ZH, Shih CY, Giamarchi T, Hulet RG. Measurement of the Dynamical Structure Factor of a 1D Interacting Fermi Gas. PHYSICAL REVIEW LETTERS 2018; 121:103001. [PMID: 30240232 DOI: 10.1103/physrevlett.121.103001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/14/2018] [Indexed: 06/08/2023]
Abstract
We present measurements of the dynamical structure factor S(q,ω) of an interacting one-dimensional Fermi gas for small excitation energies. We use the two lowest hyperfine levels of the ^{6}Li atom to form a pseudospin-1/2 system whose s-wave interactions are tunable via a Feshbach resonance. The atoms are confined to one dimension by a two-dimensional optical lattice. Bragg spectroscopy is used to measure a response of the gas to density ("charge") mode excitations at a momentum q and frequency ω, as a function of the interaction strength. The spectrum is obtained by varying ω, while the angle between two laser beams determines q, which is fixed to be less than the Fermi momentum k_{F}. The measurements agree well with Tomonaga-Luttinger theory.
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Affiliation(s)
- T L Yang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - P Grišins
- Department of Quantum Matter Physics, University of Geneva, 1211 Genève, Switzerland
| | - Y T Chang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Z H Zhao
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - C Y Shih
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - T Giamarchi
- Department of Quantum Matter Physics, University of Geneva, 1211 Genève, Switzerland
| | - R G Hulet
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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30
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Roussely G, Arrighi E, Georgiou G, Takada S, Schalk M, Urdampilleta M, Ludwig A, Wieck AD, Armagnat P, Kloss T, Waintal X, Meunier T, Bäuerle C. Unveiling the bosonic nature of an ultrashort few-electron pulse. Nat Commun 2018; 9:2811. [PMID: 30022067 PMCID: PMC6052057 DOI: 10.1038/s41467-018-05203-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/12/2018] [Indexed: 11/09/2022] Open
Abstract
Quantum dynamics is very sensitive to dimensionality. While two-dimensional electronic systems form Fermi liquids, one-dimensional systems—Tomonaga–Luttinger liquids—are described by purely bosonic excitations, even though they are initially made of fermions. With the advent of coherent single-electron sources, the quantum dynamics of such a liquid is now accessible at the single-electron level. Here, we report on time-of-flight measurements of ultrashort few-electron charge pulses injected into a quasi one-dimensional quantum conductor. By changing the confinement potential we can tune the system from the one-dimensional Tomonaga–Luttinger liquid limit to the multi-channel Fermi liquid and show that the plasmon velocity can be varied over almost an order of magnitude. These results are in quantitative agreement with a parameter-free theory and demonstrate a powerful probe for directly investigating real-time dynamics of fractionalisation phenomena in low-dimensional conductors. Electronic excitations in low-dimensional quantum nanoelectronic devices are collective waves that are strongly affected by the Coulomb interaction. Here, the authors demonstrate that they are able to prepare these collective excitations down to the single electron level and control their propagation.
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Affiliation(s)
- Gregoire Roussely
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France
| | - Everton Arrighi
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France
| | - Giorgos Georgiou
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France.,Univ. Savoie Mont-Blanc, CNRS, IMEP-LAHC, 73370, Le Bourget du Lac, France
| | - Shintaro Takada
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France.,National Institute of Advanced Industrial Science and Technology (AIST), National Metrology Institute of Japan (NMIJ), Tsukuba, Ibaraki, 305-8563, Japan
| | - Martin Schalk
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France
| | - Matias Urdampilleta
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780, Bochum, Germany
| | - Pacome Armagnat
- Univ. Grenoble Alpes, CEA, INAC-Pheliqs, 38000, Grenoble, France
| | - Thomas Kloss
- Univ. Grenoble Alpes, CEA, INAC-Pheliqs, 38000, Grenoble, France
| | - Xavier Waintal
- Univ. Grenoble Alpes, CEA, INAC-Pheliqs, 38000, Grenoble, France
| | - Tristan Meunier
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France
| | - Christopher Bäuerle
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000, Grenoble, France.
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31
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Annadi A, Cheng G, Lee H, Lee JW, Lu S, Tylan-Tyler A, Briggeman M, Tomczyk M, Huang M, Pekker D, Eom CB, Irvin P, Levy J. Quantized Ballistic Transport of Electrons and Electron Pairs in LaAlO 3/SrTiO 3 Nanowires. NANO LETTERS 2018; 18:4473-4481. [PMID: 29924620 DOI: 10.1021/acs.nanolett.8b01614] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
SrTiO3-based heterointerfaces support quasi-two-dimensional (2D) electron systems that are analogous to III-V semiconductor heterostructures, but also possess superconducting, magnetic, spintronic, ferroelectric, and ferroelastic degrees of freedom. Despite these rich properties, the relatively low mobilities of 2D complex-oxide interfaces appear to preclude ballistic transport in 1D. Here we show that the 2D LaAlO3/SrTiO3 interface can support quantized ballistic transport of electrons and (nonsuperconducting) electron pairs within quasi-1D structures that are created using a well-established conductive atomic-force microscope (c-AFM) lithography technique. The nature of transport ranges from truly single-mode (1D) to three-dimensional (3D), depending on the applied magnetic field and gate voltage. Quantization of the lowest e2/ h plateau indicate a ballistic mean-free path lMF ∼ 20 μm, more than 2 orders of magnitude larger than for 2D LaAlO3/SrTiO3 heterostructures. Nonsuperconducting electron pairs are found to be stable in magnetic fields as high as B = 11 T and propagate ballistically with conductance quantized at 2 e2/ h. Theories of one-dimensional (1D) transport of interacting electron systems depend crucially on the sign of the electron-electron interaction, which may help explain the highly ballistic transport behavior. The 1D geometry yields new insights into the electronic structure of the LaAlO3/SrTiO3 system and offers a new platform for the study of strongly interacting 1D electronic systems.
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Affiliation(s)
- Anil Annadi
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
| | - Guanglei Cheng
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics , University of Science and Technology of China , Hefei 230026 , China
| | - Hyungwoo Lee
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Jung-Woo Lee
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Shicheng Lu
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
| | - Anthony Tylan-Tyler
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
| | - Megan Briggeman
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
| | - Michelle Tomczyk
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
| | - Mengchen Huang
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
| | - David Pekker
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
| | - Chang-Beom Eom
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Patrick Irvin
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
| | - Jeremy Levy
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 United States
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32
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Landau LA, Cornfeld E, Sela E. Charge Fractionalization in the Two-Channel Kondo Effect. PHYSICAL REVIEW LETTERS 2018; 120:186801. [PMID: 29775350 DOI: 10.1103/physrevlett.120.186801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Indexed: 06/08/2023]
Abstract
The phenomenon of charge fractionalization describes the emergence of novel excitations with fractional quantum numbers, as predicted in strongly correlated systems such as spin liquids. We elucidate that precisely such an unusual effect may occur in the simplest possible non-Fermi liquid, the two-channel Kondo effect. To bring this concept down to experimental test, we study nonequilibrium transport through a device realizing the charge two-channel Kondo critical point in a recent experiment by Iftikhar et al. [Nature (London) 526, 233 (2015)NATUAS0028-083610.1038/nature15384]. The shot noise at low voltages is predicted to result in a universal Fano factor e^{*}/e=1/2. This allows us to experimentally identify elementary transport processes of emergent fermions carrying half-integer charge.
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Affiliation(s)
- L Aviad Landau
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, IL-69978 Tel Aviv, Israel
| | - Eyal Cornfeld
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, IL-69978 Tel Aviv, Israel
| | - Eran Sela
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, IL-69978 Tel Aviv, Israel
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33
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Bäuerle C, Christian Glattli D, Meunier T, Portier F, Roche P, Roulleau P, Takada S, Waintal X. Coherent control of single electrons: a review of current progress. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:056503. [PMID: 29355831 DOI: 10.1088/1361-6633/aaa98a] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this report we review the present state of the art of the control of propagating quantum states at the single-electron level and its potential application to quantum information processing. We give an overview of the different approaches that have been developed over the last few years in order to gain full control over a propagating single-electron in a solid-state system. After a brief introduction of the basic concepts, we present experiments on flying qubit circuits for ensemble of electrons measured in the low frequency (DC) limit. We then present the basic ingredients necessary to realise such experiments at the single-electron level. This includes a review of the various single-electron sources that have been developed over the last years and which are compatible with integrated single-electron circuits. This is followed by a review of recent key experiments on electron quantum optics with single electrons. Finally we will present recent developments in the new physics that has emerged using ultrashort voltage pulses. We conclude our review with an outlook and future challenges in the field.
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Affiliation(s)
- Christopher Bäuerle
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
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34
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Diaz-Marquez A, Battaglia S, Bendazzoli GL, Evangelisti S, Leininger T, Berger JA. Signatures of Wigner localization in one-dimensional systems. J Chem Phys 2018; 148:124103. [PMID: 29604812 DOI: 10.1063/1.5017118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We propose a simple and efficient approach to study Wigner localization in one-dimensional systems using ab initio theory. In particular, we propose a suitable basis for the study of localization which consists of equally spaced overlapping gaussians. We illustrate our approach with full-configuration interaction which yields exact results for a given basis set. With our approach, we were able to study up to 8 electrons with full-configuration interaction. Finally, we propose the total-position spread tensor and the total electron entropy as convenient quantities to obtain signatures of Wigner localization.
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Affiliation(s)
- Alejandro Diaz-Marquez
- Laboratoire de Chimie et Physique Quantiques, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Stefano Battaglia
- Laboratoire de Chimie et Physique Quantiques, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | | | - Stefano Evangelisti
- Laboratoire de Chimie et Physique Quantiques, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Thierry Leininger
- Laboratoire de Chimie et Physique Quantiques, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - J A Berger
- Laboratoire de Chimie et Physique Quantiques, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
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35
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James AJA, Konik RM, Lecheminant P, Robinson NJ, Tsvelik AM. Non-perturbative methodologies for low-dimensional strongly-correlated systems: From non-Abelian bosonization to truncated spectrum methods. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:046002. [PMID: 29480168 DOI: 10.1088/1361-6633/aa91ea] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We review two important non-perturbative approaches for extracting the physics of low-dimensional strongly correlated quantum systems. Firstly, we start by providing a comprehensive review of non-Abelian bosonization. This includes an introduction to the basic elements of conformal field theory as applied to systems with a current algebra, and we orient the reader by presenting a number of applications of non-Abelian bosonization to models with large symmetries. We then tie this technique into recent advances in the ability of cold atomic systems to realize complex symmetries. Secondly, we discuss truncated spectrum methods for the numerical study of systems in one and two dimensions. For one-dimensional systems we provide the reader with considerable insight into the methodology by reviewing canonical applications of the technique to the Ising model (and its variants) and the sine-Gordon model. Following this we review recent work on the development of renormalization groups, both numerical and analytical, that alleviate the effects of truncating the spectrum. Using these technologies, we consider a number of applications to one-dimensional systems: properties of carbon nanotubes, quenches in the Lieb-Liniger model, 1 + 1D quantum chromodynamics, as well as Landau-Ginzburg theories. In the final part we move our attention to consider truncated spectrum methods applied to two-dimensional systems. This involves combining truncated spectrum methods with matrix product state algorithms. We describe applications of this method to two-dimensional systems of free fermions and the quantum Ising model, including their non-equilibrium dynamics.
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Affiliation(s)
- Andrew J A James
- London Centre for Nanotechnology, University College London, Gordon Street, London WC1H 0AH, United Kingdom
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36
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Nuss J, Señarís‐Rodríguez MA, Klemenz S, Jansen M. Novel Manganate Cs
23
Mn
16
O
28
Containing Two Different Types of
Quasi
One‐Dimensional Polyanions,
1
∞
[MnO
2
]
n
and Unique
1
∞
[Mn
3
O
5
]
n
. Z Anorg Allg Chem 2017. [DOI: 10.1002/zaac.201700159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jürgen Nuss
- Max‐Planck‐Institut für Festkörperforschung Heisenbergstraße 1 70569 Stuttgart Germany
| | | | - Sebastian Klemenz
- Max‐Planck‐Institut für Chemische Physik fester Stoffe Nöthnitzer Straße 40 01187 Dresden Germany
| | - Martin Jansen
- Max‐Planck‐Institut für Festkörperforschung Heisenbergstraße 1 70569 Stuttgart Germany
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37
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Zhang Y, Zhang Q, Schwingenschlögl U. Spin-Charge Separation in Finite Length Metallic Carbon Nanotubes. NANO LETTERS 2017; 17:6747-6751. [PMID: 29039674 DOI: 10.1021/acs.nanolett.7b02880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Using time-dependent density functional theory, we study the optical excitations in finite length carbon nanotubes. Evidence of spin-charge separation is given in the spacetime domain. We demonstrate that the charge density wave is due to collective excitations of electron singlets, while the accompanying spin density wave is due to those of electron triplets. The Tomonaga-Luttinger liquid parameter and density-density interaction are extrapolated from the first-principles excitation energies. We show that the density-density interaction increases with the length of the nanotube. The singlet and triplet excitation energies, on the other hand, decrease for increasing length of the nanotube. Their ratio is used to establish a first-principles approach for deriving the Tomonaga-Luttinger parameter (in excellent agreement with experimental data). Time evolution analysis of the charge and spin line densities evidences that the charge and spin density waves are elementary excitations of metallic carbon nanotubes. Their dynamics show no dependence on each other.
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Affiliation(s)
- Yongyou Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
- Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems and School of Physics, Beijing Institute of Technology , Beijing 100081, China
| | - Qingyun Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Udo Schwingenschlögl
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
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38
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Hilker TA, Salomon G, Grusdt F, Omran A, Boll M, Demler E, Bloch I, Gross C. Revealing hidden antiferromagnetic correlations in doped Hubbard chains via string correlators. Science 2017; 357:484-487. [DOI: 10.1126/science.aam8990] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 07/06/2017] [Indexed: 11/02/2022]
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39
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Mirza MM, Schupp FJ, Mol JA, MacLaren DA, Briggs GAD, Paul DJ. One dimensional transport in silicon nanowire junction-less field effect transistors. Sci Rep 2017; 7:3004. [PMID: 28592820 PMCID: PMC5462787 DOI: 10.1038/s41598-017-03138-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/25/2017] [Indexed: 11/09/2022] Open
Abstract
Junction-less nanowire transistors are being investigated to solve short channel effects in future CMOS technology. Here we demonstrate 8 nm diameter silicon nanowire junction-less transistors with metallic doping densities which demonstrate clear 1D electronic transport characteristics. The 1D regime allows excellent gate modulation with near ideal subthreshold slopes, on- to off-current ratios above 108 and high on-currents at room temperature. Universal conductance scaling as a function of voltage and temperature similar to previous reports of Luttinger liquids and Coulomb gap behaviour at low temperatures suggests that many body effects including electron-electron interactions are important in describing the electronic transport. This suggests that modelling of such nanowire devices will require 1D models which include many body interactions to accurately simulate the electronic transport to optimise the technology but also suggest that 1D effects could be used to enhance future transistor performance.
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Affiliation(s)
- Muhammad M Mirza
- University of Glasgow, School of Engineering, Rankine Building, Oakfield Avenue, Glasgow, G12 8LT, UK
| | - Felix J Schupp
- Department of Materials, University of Oxford, 16 Parks Road, Oxford, OX1 3PH, UK
| | - Jan A Mol
- Department of Materials, University of Oxford, 16 Parks Road, Oxford, OX1 3PH, UK
| | - Donald A MacLaren
- University of Glasgow, SUPA School of Physics and Astronomy, Kelvin Building, University Avenue, Glasgow, G12 8QQ, UK
| | - G Andrew D Briggs
- Department of Materials, University of Oxford, 16 Parks Road, Oxford, OX1 3PH, UK
| | - Douglas J Paul
- University of Glasgow, School of Engineering, Rankine Building, Oakfield Avenue, Glasgow, G12 8LT, UK.
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40
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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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41
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Kwapiński T. DOS cones along atomic chains. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:095304. [PMID: 28002044 DOI: 10.1088/1361-648x/aa5540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The electron transport properties of a linear atomic chain are studied theoretically within the tight-binding Hamiltonian and the Green's function method. Variations of the local density of states (DOS) along the chain are investigated. They are crucial in scanning tunnelling experiments and give important insight into the electron transport mechanism and charge distribution inside chains. It is found that depending on the chain parity the local DOS at the Fermi level can form cone-like structures (DOS cones) along the chain. The general condition for the local DOS oscillations is obtained and the linear behaviour of the local density function is confirmed analytically. DOS cones are characterized by a linear decay towards the chain which is in contrast to the propagation properties of charge density waves, end states and Friedel oscillations in one-dimensional systems. We find that DOS cones can appear due to non-resonant electron transport, the spin-orbit scattering or for chains fabricated on a substrate with localized electrons. It is also shown that for imperfect chains (e.g. with a reduced coupling strength between two neighboring sites) a diamond-like structure of the local DOS along the chain appears.
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Affiliation(s)
- Tomasz Kwapiński
- Institute of Physics, M. Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 1, PL-20-031 Lublin, Poland
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42
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Ma Y, Diaz HC, Avila J, Chen C, Kalappattil V, Das R, Phan MH, Čadež T, Carmelo JMP, Asensio MC, Batzill M. Angle resolved photoemission spectroscopy reveals spin charge separation in metallic MoSe 2 grain boundary. Nat Commun 2017; 8:14231. [PMID: 28165445 PMCID: PMC5303875 DOI: 10.1038/ncomms14231] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 12/09/2016] [Indexed: 11/20/2022] Open
Abstract
Material line defects are one-dimensional structures but the search and proof of electron behaviour consistent with the reduced dimension of such defects has been so far unsuccessful. Here we show using angle resolved photoemission spectroscopy that twin-grain boundaries in the layered semiconductor MoSe2 exhibit parabolic metallic bands. The one-dimensional nature is evident from a charge density wave transition, whose periodicity is given by kF/π, consistent with scanning tunnelling microscopy and angle resolved photoemission measurements. Most importantly, we provide evidence for spin- and charge-separation, the hallmark of one-dimensional quantum liquids. Our studies show that the spectral line splits into distinctive spinon and holon excitations whose dispersions exactly follow the energy-momentum dependence calculated by a Hubbard model with suitable finite-range interactions. Our results also imply that quantum wires and junctions can be isolated in line defects of other transition metal dichalcogenides, which may enable quantum transport measurements and devices. Line defects are 1D structures often embedded within 2D materials. Here, the authors use angle resolved photoemission spectroscopy to unveil the 1D nature of electron behaviour in such defects in atomically thin MoS2, providing evidence for spin- and charge-separation.
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Affiliation(s)
- Yujing Ma
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
| | - Horacio Coy Diaz
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
| | - José Avila
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin-BP 48, Gif sur Yvette Cedex 91192, France.,Université Paris-Saclay, L'Orme des Merisiers, Saint Aubin-BP 48, Gif sur Yvette Cedex 91192, France
| | - Chaoyu Chen
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin-BP 48, Gif sur Yvette Cedex 91192, France.,Université Paris-Saclay, L'Orme des Merisiers, Saint Aubin-BP 48, Gif sur Yvette Cedex 91192, France
| | | | - Raja Das
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
| | - Manh-Huong Phan
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
| | - Tilen Čadež
- Beijing Computational Science Research Center, Beijing 100193, China.,Center of Physics of University of Minho and University of Porto, Oporto P-4169-007, Portugal
| | - José M P Carmelo
- Beijing Computational Science Research Center, Beijing 100193, China.,Center of Physics of University of Minho and University of Porto, Oporto P-4169-007, Portugal.,Department of Physics, University of Minho, Campus Gualtar, Braga P-4710-057, Portugal
| | - Maria C Asensio
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin-BP 48, Gif sur Yvette Cedex 91192, France.,Université Paris-Saclay, L'Orme des Merisiers, Saint Aubin-BP 48, Gif sur Yvette Cedex 91192, France
| | - Matthias Batzill
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
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43
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Nonlinear spectra of spinons and holons in short GaAs quantum wires. Nat Commun 2016; 7:12784. [PMID: 27627993 PMCID: PMC5027612 DOI: 10.1038/ncomms12784] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 08/02/2016] [Indexed: 11/13/2022] Open
Abstract
One-dimensional electronic fluids are peculiar conducting systems, where the fundamental role of interactions leads to exotic, emergent phenomena, such as spin-charge (spinon-holon) separation. The distinct low-energy properties of these 1D metals are successfully described within the theory of linear Luttinger liquids, but the challenging task of describing their high-energy nonlinear properties has long remained elusive. Recently, novel theoretical approaches accounting for nonlinearity have been developed, yet the rich phenomenology that they predict remains barely explored experimentally. Here, we probe the nonlinear spectral characteristics of short GaAs quantum wires by tunnelling spectroscopy, using an advanced device consisting of 6000 wires. We find evidence for the existence of an inverted (spinon) shadow band in the main region of the particle sector, one of the central predictions of the new nonlinear theories. A (holon) band with reduced effective mass is clearly visible in the particle sector at high energies. Recently, theories have emerged that describe the nonlinear high-energy excitations of one-dimensional electronic fluids. Here, the authors report experimental evidence of their existence and behaviour in tunnelling spectra of short GaAs quantum wires.
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44
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Chudow JD, Santavicca DF, Prober DE. Terahertz Spectroscopy of Individual Single-Walled Carbon Nanotubes as a Probe of Luttinger Liquid Physics. NANO LETTERS 2016; 16:4909-4916. [PMID: 27439013 DOI: 10.1021/acs.nanolett.6b01485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Luttinger liquid theory predicts that collective electron excitations due to strong electron-electron interactions in a one-dimensional (1D) system will result in a modification of the collective charge-propagation velocity. By utilizing a circuit model for an individual metallic single-walled carbon nanotube as a nanotransmission line, it has been shown that the frequency-dependent terahertz impedance of a carbon nanotube can probe this expected 1D Luttinger liquid behavior. We excite terahertz standing-wave resonances on individual antenna-coupled metallic single-walled carbon nanotubes. The terahertz signal is rectified using the nanotube contact nonlinearity, allowing for a low-frequency readout of the coupled terahertz current. The charge velocity on the nanotube is determined from the terahertz spectral response. Our measurements show that a carbon nanotube can behave as a Luttinger liquid system with charge-propagation velocities that are faster than the Fermi velocity. Understanding what determines the charge velocity in low-dimensional conductors is important for the development of next generation nanodevices.
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Affiliation(s)
- Joel D Chudow
- Department of Applied Physics, Yale University , New Haven, Connecticut 06511, United States
| | - Daniel F Santavicca
- Department of Applied Physics, Yale University , New Haven, Connecticut 06511, United States
- Department of Physics, University of North Florida , Jacksonville, Florida 32224, United States
| | - Daniel E Prober
- Department of Applied Physics, Yale University , New Haven, Connecticut 06511, United States
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45
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Xi S, Jie W, Zha G, Yuan Y, Wang T, Zhang W, Zhu J, Xu L, Xu Y, Su J, Zhang H, Gu Y, Li J, Ren J, Zhao Q. Effects of Ga-Te interface layer on the potential barrier height of CdTe/GaAs heterointerface. Phys Chem Chem Phys 2016; 18:2639-45. [PMID: 26699197 DOI: 10.1039/c5cp04802h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interface layer has great significance on the potential barrier height of the CdTe/GaAs heterointerface. In this study, the electronic properties of the CdTe/GaAs heterostructure prepared by molecular beam epitaxy was investigated in situ by synchrotron radiation photoemission spectroscopy for CdTe thicknesses ranging from 3.5 to 74.6 Å. During CdTe deposition, an As-Te and Ga-Te interface reaction occurred, which caused the out diffusion of Ga. As a result a stable GaTe interface dipole layer (more than 30 Å) was formed, which reduced the potential barrier height by 0.38 eV. The potential barrier height was in proportion to the chemical bonding density and thickness of the Ga-Te interface layer. These results provide a more fundamental understanding of the influencing mechanism of the interface layer on the potential barrier height of the CdTe/GaAs heterointerface.
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Affiliation(s)
- Shouzhi Xi
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Wanqi Jie
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Gangqiang Zha
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Yanyan Yuan
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
| | - Tao Wang
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Wenhua Zhang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Junfa Zhu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
| | - Lingyan Xu
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Yadong Xu
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Jie Su
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
| | - Hao Zhang
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Yaxu Gu
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Jiawei Li
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
| | - Jie Ren
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
| | - Qinghua Zhao
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China. and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, China
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46
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Duc PF, Savard M, Petrescu M, Rosenow B, Del Maestro A, Gervais G. Critical flow and dissipation in a quasi-one-dimensional superfluid. SCIENCE ADVANCES 2015; 1:e1400222. [PMID: 26601177 PMCID: PMC4640651 DOI: 10.1126/sciadv.1400222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/08/2015] [Indexed: 06/05/2023]
Abstract
In one of the most celebrated examples of the theory of universal critical phenomena, the phase transition to the superfluid state of (4)He belongs to the same three-dimensional (3D) O(2) universality class as the onset of ferromagnetism in a lattice of classical spins with XY symmetry. Below the transition, the superfluid density ρs and superfluid velocity v s increase as a power law of temperature described by a universal critical exponent that is constrained to be identical by scale invariance. As the dimensionality is reduced toward 1D, it is expected that enhanced thermal and quantum fluctuations preclude long-range order, thereby inhibiting superfluidity. We have measured the flow rate of liquid helium and deduced its superfluid velocity in a capillary flow experiment occurring in single 30-nm-long nanopores with radii ranging down from 20 to 3 nm. As the pore size is reduced toward the 1D limit, we observe the following: (i) a suppression of the pressure dependence of the superfluid velocity; (ii) a temperature dependence of v s that surprisingly can be well-fitted by a power law with a single exponent over a broad range of temperatures; and (iii) decreasing critical velocities as a function of decreasing radius for channel sizes below R ≃ 20 nm, in stark contrast with what is observed in micrometer-sized channels. We interpret these deviations from bulk behavior as signaling the crossover to a quasi-1D state, whereby the size of a critical topological defect is cut off by the channel radius.
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Affiliation(s)
| | - Michel Savard
- Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada
| | - Matei Petrescu
- Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada
| | - Bernd Rosenow
- Institut für Theoretische Physik, Universität Leipzig, D-04103 Leipzig, Germany
| | | | - Guillaume Gervais
- Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada
- Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
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47
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Scheller CP, Liu TM, Barak G, Yacoby A, Pfeiffer LN, West KW, Zumbühl DM. Possible evidence for helical nuclear spin order in GaAs quantum wires. PHYSICAL REVIEW LETTERS 2014; 112:066801. [PMID: 24580700 DOI: 10.1103/physrevlett.112.066801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Indexed: 06/03/2023]
Abstract
We present transport measurements of cleaved edge overgrowth GaAs quantum wires. The conductance of the first mode reaches 2e(2)/h at high temperatures T≳10 K, as expected. As T is lowered, the conductance is gradually reduced to 1e(2)/h, becoming T independent at T≲0.1 K, while the device cools far below 0.1 K. This behavior is seen in several wires, is independent of density, and not altered by moderate magnetic fields B. The conductance reduction by a factor of 2 suggests lifting of the electron spin degeneracy in the absence of B. Our results are consistent with theoretical predictions for helical nuclear magnetism in the Luttinger liquid regime.
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Affiliation(s)
- C P Scheller
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - T-M Liu
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - G Barak
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - A Yacoby
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - L N Pfeiffer
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - K W West
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - D M Zumbühl
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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48
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Laroche D, Gervais G, Lilly MP, Reno JL. 1D-1D Coulomb Drag Signature of a Luttinger Liquid. Science 2014; 343:631-4. [DOI: 10.1126/science.1244152] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- D. Laroche
- Department of Physics, McGill University, Montreal, H3A 2T8 Canada
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA
| | - G. Gervais
- Department of Physics, McGill University, Montreal, H3A 2T8 Canada
| | - M. P. Lilly
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA
| | - J. L. Reno
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA
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49
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Matveev KA, Furusaki A. Decay of fermionic quasiparticles in one-dimensional quantum liquids. PHYSICAL REVIEW LETTERS 2013; 111:256401. [PMID: 24483750 DOI: 10.1103/physrevlett.111.256401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Indexed: 06/03/2023]
Abstract
The low-energy properties of one-dimensional quantum liquids are commonly described in terms of the Tomonaga-Luttinger liquid theory, in which the elementary excitations are free bosons. To this approximation, the theory can be alternatively recast in terms of free fermions. In both approaches, small perturbations give rise to finite lifetimes of excitations. We evaluate the decay rate of fermionic excitations and show that it scales as the eighth power of energy, in contrast to the much faster decay of bosonic excitations. Our results can be tested experimentally by measuring the broadening of power-law features in the density structure factor or spectral functions.
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Affiliation(s)
- K A Matveev
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Furusaki
- Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198, Japan and RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
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50
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Yager B, Nyéki J, Casey A, Cowan BP, Lusher CP, Saunders J. NMR signature of one-dimensional behavior of 3He in nanopores. PHYSICAL REVIEW LETTERS 2013; 111:215303. [PMID: 24313498 DOI: 10.1103/physrevlett.111.215303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Indexed: 06/02/2023]
Abstract
We have performed thermodynamic and NMR relaxation time measurements of 3He adsorbed in the pores of the mesoporous molecular sieve MCM-41 at temperatures down to 1.7 K and at a range of frequencies up to 240 kHz. The MCM-41 substrate comprises a uniform array of quasi-1D straight pores with a diameter of 2.3 nm. We preplated the pores with a monolayer of 4He to achieve an effective diameter of 1.6 nm at low temperatures. We made NMR measurements as a function of line density and frequency to investigate the spin dynamics and the effect of dimensionality. We observed T(1) is proportional to ω1/2, which is characteristic of one-dimensional diffusion. At these temperatures this arises from a classical size effect in the narrow pores. Our results demonstrate the possibility to study the spin dynamics of a 1D Tomonaga-Luttinger liquid at lower temperatures, where the 3He liquid will constitute a quantum 1D system.
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Affiliation(s)
- B Yager
- Department of Physics, Royal Holloway University of London, Egham, Surrey TW20 0EX, United Kingdom
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