1251
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Yokoyama T, Tanaka Y, Nagaosa N. Giant spin rotation in the junction between a normal metal and a quantum spin Hall system. PHYSICAL REVIEW LETTERS 2009; 102:166801. [PMID: 19518736 DOI: 10.1103/physrevlett.102.166801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Indexed: 05/27/2023]
Abstract
We study theoretically the reflection problem in the junction between a normal metal and an insulator characterized by a parameter M, which is a usual insulator for M>0 or a quantum-spin-Hall system for M<0. The spin rotation angle alpha at the reflection is obtained as a function of M and the incident angle theta measured from the normal to the interface. The alpha shows rich structures around the quantum critical point M=0 and theta=0; i.e., alpha can be as large as approximately pi at an incident angle in the quantum spin Hall case M<0 because the helical edge modes resonantly enhance the spin rotation, which can be used to map the energy dispersion of the helical edge modes. As an experimentally relevant system, we also study the spin rotation effect in quantum-spin-Hall-normal-metal-quantum-spin-Hall trilayer junction.
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Affiliation(s)
- Takehito Yokoyama
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
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1252
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Liu Q, Liu CX, Xu C, Qi XL, Zhang SC. Magnetic impurities on the surface of a topological insulator. PHYSICAL REVIEW LETTERS 2009; 102:156603. [PMID: 19518663 DOI: 10.1103/physrevlett.102.156603] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Indexed: 05/27/2023]
Abstract
The surface states of a topological insulator are described by an emergent relativistic massless Dirac equation in 2 + 1 dimensions. In contrast with graphene, there is an odd number of Dirac points, and the electron spin is directly coupled to the momentum. We show that a magnetic impurity opens up a local gap and suppresses the local density of states. Furthermore, the Dirac electronic states mediate an RKKY interaction among the magnetic impurities which is always ferromagnetic, whenever the chemical potential lies near the Dirac point. Through this exchange mechanism, magnetic atoms uniformly deposited on the surface of a topological insulator could naturally form a ferromagnetically ordered film. These effects can be directly measured in STM experiments. We also study the case of quenched disorder through a renormalization group analysis.
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Affiliation(s)
- Qin Liu
- Department of Physics, Fudan University, Shanghai 200433, China
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1253
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Li J, Chu RL, Jain JK, Shen SQ. Topological Anderson insulator. PHYSICAL REVIEW LETTERS 2009; 102:136806. [PMID: 19392389 DOI: 10.1103/physrevlett.102.136806] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Indexed: 05/27/2023]
Abstract
Disorder plays an important role in two dimensions, and is responsible for striking phenomena such as metal-insulator transition and the integral and fractional quantum Hall effects. In this Letter, we investigate the role of disorder in the context of the recently discovered topological insulator, which possesses a pair of helical edge states with opposing spins moving in opposite directions and exhibits the phenomenon of quantum spin Hall effect. We predict an unexpected and nontrivial quantum phase termed "topological Anderson insulator," which is obtained by introducing impurities in a two-dimensional metal; here disorder not only causes metal-insulator transition, as anticipated, but is fundamentally responsible for creating extended edge states. We determine the phase diagram of the topological Anderson insulator and outline its experimental consequences.
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Affiliation(s)
- Jian Li
- Department of Physics and Center of Computational and Theoretical Physics, The University of Hong Kong, Pokfulam Road, Hong Kong
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1254
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Bermudez A, Patanè D, Amico L, Martin-Delgado MA. Topology-induced anomalous defect production by crossing a quantum critical point. PHYSICAL REVIEW LETTERS 2009; 102:135702. [PMID: 19392370 DOI: 10.1103/physrevlett.102.135702] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 01/15/2009] [Indexed: 05/27/2023]
Abstract
We study the influence of topology on the quench dynamics of a system driven across a quantum critical point. We show how the appearance of certain edge states, which fully characterize the topology of the system, dramatically modifies the process of defect production during the crossing of the critical point. Interestingly enough, the density of defects is no longer described by the Kibble-Zurek scaling, but determined instead by the nonuniversal topological features of the system. Edge states are shown to be robust against defect production, which highlights their topological nature.
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Affiliation(s)
- A Bermudez
- Departamento de Física Teórica I, Universidad Complutense, 28040 Madrid, Spain
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1255
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Wells JW, Dil JH, Meier F, Lobo-Checa J, Petrov VN, Osterwalder J, Ugeda MM, Fernandez-Torrente I, Pascual JI, Rienks EDL, Jensen MF, Hofmann P. Nondegenerate metallic States on Bi(114): a one-dimensional topological metal. PHYSICAL REVIEW LETTERS 2009; 102:096802. [PMID: 19392548 DOI: 10.1103/physrevlett.102.096802] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Indexed: 05/27/2023]
Abstract
The (114) surface of the semimetal Bi is found to support a quasi-one-dimensional, metallic surface state. As required by symmetry, the state is degenerate along the Gamma-Y line of the surface Brillouin zone with a highest binding energy of approximately 150 meV. In the Gamma-X direction the degeneracy is lifted by the strong spin-orbit splitting in Bi, as directly shown by spin-resolved photoemission. This results in a Fermi contour consisting of two closely separated, parallel lines of opposite spin direction. It is argued that similar states on related insulators would give rise to a one-dimensional quantum spin Hall effect.
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Affiliation(s)
- J W Wells
- Institute for Storage Ring Facilities (ISA) and Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, 8000 Aarhus C, Denmark
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1256
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Ström A, Johannesson H. Tunneling between edge states in a quantum spin Hall system. PHYSICAL REVIEW LETTERS 2009; 102:096806. [PMID: 19392552 DOI: 10.1103/physrevlett.102.096806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Indexed: 05/27/2023]
Abstract
We analyze a quantum spin Hall device with a point contact connecting two of its edges. The contact supports a net spin tunneling current that can be probed experimentally via a two-terminal resistance measurement. We find that the low-bias tunneling current and the differential conductance exhibit scaling with voltage and temperature that depend nonlinearly on the strength of the electron-electron interaction.
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Affiliation(s)
- Anders Ström
- Department of Physics, University of Gothenburg, SE 412 96 Gothenburg, Sweden
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1257
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Qi XL, Li R, Zang J, Zhang SC. Inducing a Magnetic Monopole with Topological Surface States. Science 2009; 323:1184-7. [DOI: 10.1126/science.1167747] [Citation(s) in RCA: 745] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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1258
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Hou CY, Kim EA, Chamon C. Corner junction as a probe of helical edge states. PHYSICAL REVIEW LETTERS 2009; 102:076602. [PMID: 19257702 DOI: 10.1103/physrevlett.102.076602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Indexed: 05/27/2023]
Abstract
We propose and analyze interedge tunneling in a quantum spin Hall corner junction as a means to probe the helical nature of the edge states. We show that electron-electron interactions in the one-dimensional helical edge states result in Luttinger parameters for spin and charge that are intertwined, and thus rather different from those for a quantum wire with spin rotation invariance. Consequently, we find that the four-terminal conductance in a corner junction has a distinctive form that could be used as evidence for the helical nature of the edge states.
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Affiliation(s)
- Chang-Yu Hou
- Physics Department, Boston University, Boston, Massachusetts 02215, USA
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1259
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Affiliation(s)
- Jan Zaanen
- Lorentz Institute for Theoretical Physics, Leiden University, 2300 RA Leiden, Netherlands
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1260
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Hsieh D, Xia Y, Wray L, Qian D, Pal A, Dil JH, Osterwalder J, Meier F, Bihlmayer G, Kane CL, Hor YS, Cava RJ, Hasan MZ. Observation of Unconventional Quantum Spin Textures in Topological Insulators. Science 2009; 323:919-22. [DOI: 10.1126/science.1167733] [Citation(s) in RCA: 1003] [Impact Index Per Article: 66.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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1261
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Zhou B, Lu HZ, Chu RL, Shen SQ, Niu Q. Finite size effects on helical edge states in a quantum spin-Hall system. PHYSICAL REVIEW LETTERS 2008; 101:246807. [PMID: 19113649 DOI: 10.1103/physrevlett.101.246807] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Indexed: 05/27/2023]
Abstract
The hallmark of the spin-Hall insulator is the presence of gapless edge states of different spins moving in opposite directions. Through analytical solutions in a model calculation for a strip of finite width, we find that edge states on the two sides can couple together to produce a gap in the spectrum, destroying the quantum spin-Hall effect. The application of a magnetic field can however modify and even remove the gap by shifting the momenta of the edge states relative to each other.
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Affiliation(s)
- Bin Zhou
- Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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1262
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Gao F, Wang G, Zhang C. Strong photon-mixing of terahertz waves in semiconductor quantum wells induced by Rashba spin-orbit coupling. NANOTECHNOLOGY 2008; 19:465401. [PMID: 21836243 DOI: 10.1088/0957-4484/19/46/465401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate that due to the Rashba spin-orbit coupling in semiconductor quantum wells, there is strong photo-mixing by mobile carriers in the terahertz frequency regime. The third order nonlinear current is of the same order of magnitude as the linear order current for an electric field intensity of 10(4) V cm(-1) at frequency around 1 THz, a situation easily achievable in a laboratory system. Unlike other nonlinear effects, the nonlinear current density due to the spin-orbit coupling is inversely proportional to the concentration of mobile carriers.
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Affiliation(s)
- Feng Gao
- Institute of Superconducting and Electronic Materials, University of Wollongong, New South Wales 2522, Australia
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1263
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Moore JE, Ran Y, Wen XG. Topological surface States in three-dimensional magnetic insulators. PHYSICAL REVIEW LETTERS 2008; 101:186805. [PMID: 18999850 DOI: 10.1103/physrevlett.101.186805] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Indexed: 05/27/2023]
Abstract
An electron moving in a magnetically ordered background feels an effective magnetic field that can be both stronger and more rapidly varying than typical externally applied fields. One consequence is that insulating magnetic materials in three dimensions can have topologically nontrivial properties of the effective band structure. For the simplest case of two bands, these "Hopf insulators" are characterized by a topological invariant as in quantum Hall states and Z2 topological insulators, but instead of a Chern number or parity, the underlying invariant is the Hopf invariant that classifies maps from the three-sphere to the two-sphere. This Letter gives an efficient algorithm to compute whether a given magnetic band structure has nontrivial Hopf invariant, a double-exchange-like tight-binding model that realizes the nontrivial case, and a numerical study of the surface states of this model.
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Affiliation(s)
- Joel E Moore
- Department of Physics, University of California, Berkeley, California 94720, USA
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1264
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Wu C. Orbital analogue of the quantum anomalous Hall effect in p-band systems. PHYSICAL REVIEW LETTERS 2008; 101:186807. [PMID: 18999852 DOI: 10.1103/physrevlett.101.186807] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Indexed: 05/27/2023]
Abstract
We investigate the topological insulating states of the p-band systems in optical lattices induced by the on site orbital angular momentum polarization, which exhibit gapless edge modes in the absence of Landau levels. This effect arises from the energy-level splitting between the on site p_{x}+ip_{y} and p_{x}-ip_{y} orbitals by rotating each optical lattice site around its own center. At large rotation angular velocities, this model naturally reduces to two copies of Haldane's quantum Hall model. The distribution of the Berry curvature in momentum space and the quantized Chern numbers are calculated. The experimental realization of this state is feasible.
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Affiliation(s)
- Congjun Wu
- Department of Physics, University of California, San Diego, California 92093, USA
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1265
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Liu CX, Qi XL, Dai X, Fang Z, Zhang SC. Quantum anomalous hall effect in Hg1-yMnyTe quantum wells. PHYSICAL REVIEW LETTERS 2008; 101:146802. [PMID: 18851555 DOI: 10.1103/physrevlett.101.146802] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Indexed: 05/26/2023]
Abstract
The quantum Hall effect is usually observed when a two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{1-y}Mn{y}Te quantum wells, without an external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.
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Affiliation(s)
- Chao-Xing Liu
- Center for Advanced Study, Tsinghua University, Beijing 100084, China
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1266
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Nilsson J, Akhmerov AR, Beenakker CWJ. Splitting of a Cooper pair by a pair of Majorana bound states. PHYSICAL REVIEW LETTERS 2008; 101:120403. [PMID: 18851345 DOI: 10.1103/physrevlett.101.120403] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 08/15/2008] [Indexed: 05/26/2023]
Abstract
We propose a method to probe the nonlocality of a pair of Majorana bound states by crossed Andreev reflection, which is the injection of an electron into one bound state followed by the emission of a hole by the other (equivalent to the splitting of a Cooper pair). We find that, at sufficiently low excitation energies, this nonlocal scattering process dominates over local Andreev reflection involving a single bound state. As a consequence, the low-temperature and low-frequency fluctuations deltaI(i) of currents into the two bound states i=1, 2 are maximally correlated: deltaI_1deltaI_2[over ]=deltaI_i(2).[over ].
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Affiliation(s)
- Johan Nilsson
- Instituut-Lorentz, Universiteit Leiden, Leiden, The Netherlands
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1267
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Fert A. Origin, development, and future of spintronics (Nobel Lecture). Angew Chem Int Ed Engl 2008; 47:5956-67. [PMID: 18626879 DOI: 10.1002/anie.200801093] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Albert Fert
- Unité Mixte de Physique CNRS/Thales, 91767 Palaiseau, France.
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1268
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Qi XL, Zhang SC. Spin-charge separation in the quantum spin Hall state. PHYSICAL REVIEW LETTERS 2008; 101:086802. [PMID: 18764648 DOI: 10.1103/physrevlett.101.086802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Indexed: 05/26/2023]
Abstract
The quantum spin Hall state is a topologically nontrivial insulator state protected by the time-reversal symmetry. We show that such a state always leads to spin-charge separation in the presence of a pi flux. Our result is generally valid for any interacting system. We present a proposal to experimentally observe the phenomenon of spin-charge separation in the recently discovered quantum spin Hall system.
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Affiliation(s)
- Xiao-Liang Qi
- Department of Physics, McCullough Building, Stanford University, Stanford, California 94305-4045, USA
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1269
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Ran Y, Vishwanath A, Lee DH. Spin-charge separated solitons in a topological band insulator. PHYSICAL REVIEW LETTERS 2008; 101:086801. [PMID: 18764647 DOI: 10.1103/physrevlett.101.086801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Indexed: 05/26/2023]
Abstract
In this Letter we construct a simple, controllable, two-dimensional model based on a topological band insulator. It has many attractive properties. (1) We obtain spin-charge separated solitons that are associated with dynamic pi fluxes. (2) These solitons obey Bose statistics and their condensation triggers a phase transition from a spin Hall insulator to an easy-plane ferromagnet. (3) It suggests an alternative way to classify the Z2 topological band insulator without resorting to the sample boundary.
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Affiliation(s)
- Ying Ran
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
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1270
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1271
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1272
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Liu C, Hughes TL, Qi XL, Wang K, Zhang SC. Quantum spin Hall effect in inverted type-II semiconductors. PHYSICAL REVIEW LETTERS 2008; 100:236601. [PMID: 18643529 DOI: 10.1103/physrevlett.100.236601] [Citation(s) in RCA: 166] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Indexed: 05/26/2023]
Abstract
The quantum spin Hall (QSH) state is a topologically nontrivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel effect has been predicted and observed in HgTe quantum wells and in this Letter we predict a similar effect arising in Type-II semiconductor quantum wells made from InAs/GaSb/AlSb. The quantum well exhibits an "inverted" phase similar to HgTe/CdTe quantum wells, which is a QSH state when the Fermi level lies inside the gap. Due to the asymmetric structure of this quantum well, the effects of inversion symmetry breaking are essential. Remarkably, the topological quantum phase transition between the conventional insulating state and the quantum spin Hall state can be continuously tuned by the gate voltage, enabling quantitative investigation of this novel phase transition.
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Affiliation(s)
- Chaoxing Liu
- Center for Advanced Study, Tsinghua University, Beijing, China
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1273
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A topological Dirac insulator in a quantum spin Hall phase. Nature 2008; 452:970-4. [PMID: 18432240 DOI: 10.1038/nature06843] [Citation(s) in RCA: 762] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2007] [Accepted: 02/14/2008] [Indexed: 11/09/2022]
Abstract
When electrons are subject to a large external magnetic field, the conventional charge quantum Hall effect dictates that an electronic excitation gap is generated in the sample bulk, but metallic conduction is permitted at the boundary. Recent theoretical models suggest that certain bulk insulators with large spin-orbit interactions may also naturally support conducting topological boundary states in the quantum limit, which opens up the possibility for studying unusual quantum Hall-like phenomena in zero external magnetic fields. Bulk Bi(1-x)Sb(x) single crystals are predicted to be prime candidates for one such unusual Hall phase of matter known as the topological insulator. The hallmark of a topological insulator is the existence of metallic surface states that are higher-dimensional analogues of the edge states that characterize a quantum spin Hall insulator. In addition to its interesting boundary states, the bulk of Bi(1-x)Sb(x) is predicted to exhibit three-dimensional Dirac particles, another topic of heightened current interest following the new findings in two-dimensional graphene and charge quantum Hall fractionalization observed in pure bismuth. However, despite numerous transport and magnetic measurements on the Bi(1-x)Sb(x) family since the 1960s, no direct evidence of either topological Hall states or bulk Dirac particles has been found. Here, using incident-photon-energy-modulated angle-resolved photoemission spectroscopy (IPEM-ARPES), we report the direct observation of massive Dirac particles in the bulk of Bi(0.9)Sb(0.1), locate the Kramers points at the sample's boundary and provide a comprehensive mapping of the Dirac insulator's gapless surface electron bands. These findings taken together suggest that the observed surface state on the boundary of the bulk insulator is a realization of the 'topological metal'. They also suggest that this material has potential application in developing next-generation quantum computing devices that may incorporate 'light-like' bulk carriers and spin-textured surface currents.
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1274
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Grover T, Senthil T. Topological spin Hall states, charged skyrmions, and superconductivity in two dimensions. PHYSICAL REVIEW LETTERS 2008; 100:156804. [PMID: 18518141 DOI: 10.1103/physrevlett.100.156804] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Indexed: 05/26/2023]
Abstract
We study the properties of two dimensional topological spin Hall insulators which arise through spontaneous breakdown of spin symmetry in systems that are spin rotation invariant. Such a phase breaks spin rotation but not time reversal symmetry and has a vector order parameter. Skyrmion configurations in this vector order parameter are shown to have an electric charge that is twice the electron charge. When the spin Hall order is destroyed by condensation of Skyrmions superconductivity results. This may happen either through doping or at fixed filling by tuning interactions to close the Skyrmion gap. In the latter case the superconductor-spin Hall insulator quantum phase transition can be second order even though the two phases break distinct symmetries.
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Affiliation(s)
- Tarun Grover
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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1275
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Raghu S, Qi XL, Honerkamp C, Zhang SC. Topological Mott insulators. PHYSICAL REVIEW LETTERS 2008; 100:156401. [PMID: 18518132 DOI: 10.1103/physrevlett.100.156401] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Indexed: 05/05/2023]
Abstract
We consider extended Hubbard models with repulsive interactions on a honeycomb lattice, and the transitions from the semimetal to Mott insulating phases at half-filling. Because of the frustrated nature of the second-neighbor interactions, topological Mott phases displaying the quantum Hall and the quantum spin Hall effects are found for spinless and spin fermion models, respectively. The mean-field phase diagram is presented and the fluctuations are treated within the random phase approximation. Renormalization group analysis shows that these states can be favored over the topologically trivial Mott insulating states.
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Affiliation(s)
- S Raghu
- Department of Physics, McCullough Building, Stanford University, Stanford, CA 94305-4045, USA
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1276
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Journal club. Nature 2008. [DOI: 10.1038/452391a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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1277
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Yang W, Chang K, Zhang SC. Intrinsic spin hall effect induced by quantum phase transition in HgCdTe quantum wells. PHYSICAL REVIEW LETTERS 2008; 100:056602. [PMID: 18352404 DOI: 10.1103/physrevlett.100.056602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Indexed: 05/26/2023]
Abstract
The spin Hall effect can be induced by both extrinsic impurity scattering and intrinsic spin-orbit coupling in the electronic structure. The HgTe/CdTe quantum well has a quantum phase transition where the electronic structure changes from normal to inverted. We show that the intrinsic spin Hall effect of the conduction band vanishes on the normal side, while it is finite on the inverted side. By tuning the Cd content, the well width, or the bias electric field across the quantum well, the intrinsic spin Hall effect can be switched on or off and tuned into resonance under experimentally accessible conditions.
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Affiliation(s)
- Wen Yang
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, 100083, Beijing, China
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1278
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Affiliation(s)
- Naoto Nagaosa
- The author is in the Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
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