Tuning Edge States in Strained-Layer 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>InAs</mml:mi><mml:mo>/</mml:mo><mml:mi>GaInSb</mml:mi></mml:mrow></mml:math>
 Quantum Spin Hall Insulators

Du, Lingjie; Li, Tingxin; Lou, Wenkai; Wu, Xingjun; Liu, Xiaoxue; Han, Ziyao; Zhang, Chi; Sullivan, Gerard; Ikhlassi, Amal; Chang, Kai; Du, Rui-Rui

doi:10.1103/physrevlett.119.056803

Cited by 72 publications

(81 citation statements)

References 31 publications

(64 reference statements)

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“…5, as it significantly shifts the boundary between the inverted state and the magnetic field driven normal state. Practically, the strain effect can be engineered by choosing the appropriate substrate (typically, GaSb for pseudomorphic growth, GaAs for metamorphic growth) and the epi-structure 13 . In conclusion, we have studied the LL structure of a series of InAs/GaSb DQWs from the normal to the inverted state using magneto-IR spectroscopy.…”

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confidence: 99%

Probing the semiconductor to semimetal transition in InAs/GaSb double quantum wells by magneto-infrared spectroscopy

et al. 2017

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We perform a magneto-infrared spectroscopy study of the semiconductor to semimetal transition of InAs/GaSb double quantum wells from the normal to the inverted state. We show that owing to the low carrier density of our samples (approaching the intrinsic limit), the magneto-absorption spectra evolve from a single cyclotron resonance peak in the normal state to multiple absorption peaks in the inverted state with distinct magnetic field dependence. Using an eight-band Pidgeon-Brown model, we explain all the major absorption peaks observed in our experiment. We demonstrate that the semiconductor to semimetal transition can be realized by manipulating the quantum confinement, the strain, and the magnetic field. Our work paves the way for band engineering of optimal InAs/GaSb structures for realizing novel topological states as well as for device applications in the terahertz regime.

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confidence: 99%

Probing the semiconductor to semimetal transition in InAs/GaSb double quantum wells by magneto-infrared spectroscopy

et al. 2017

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“…Changing the thickness of the InAs layer can tune the position of the subband in the quantum well. During this tuning, the quantum well changes from conventional insulator to shallowly inverted insulator, then deeply inverted insulator . The hybridization gap and observe a gap resistance close to

h / 2 e^{2}

.…”

Section: Quantum Spin Hall Effect In Quantum Wellsmentioning

confidence: 98%

“…Ref. [] reported the experimental effort along the first direction (e.g., enhancing the hybridization gap E g ) using strain engineering. In this work, strain was induced by alloying GaSb with InSb because their lattice constants are different.…”

Section: Quantum Spin Hall Effect In Quantum Wellsmentioning

confidence: 99%

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Quantum Spin Hall Materials

Cao

Chen

2019

Adv Quantum Tech

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The quantum spin Hall (QSH) effect describes the state of matter in certain 2D electron systems, in which an insulating bulk state arises together with helical states at the edge of the sample. In stark contrast to its closest kin, the integer quantum Hall state, the QSH state exists only in time‐reversal symmetric system (e.g., in non‐magnetic materials and without the application of external magnetic field). This article reviews the development of the understanding and construction of the QSH states after their first theoretical proposal, with an emphasis on the materials perspective. Certain semiconductor quantum wells and 2D materials with strong spin–orbit coupling have been found to support QSH states.

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“…Most of the previous works have focused on the impact of local spins, either magnetic impurities or nuclei, on the quasiparticle spin relaxation, which has a direct impact on the lack of conductance quantization: in the absence of spin-flip scattering, the conductance of QSH channels should be e 2 /h [26]. Experiments [27,29,34,36] very often find smaller conductance values, which motivates the quest of spin-flip back-scattering mechanisms [29,34]. There are in addition several proposals for the manipulation of nanomagnets and local magnetic impurities with the spin-transfer torque exerted by the fully spin-polarized current of QSH edges [42][43][44].…”

Section: Introductionmentioning

confidence: 99%

Enhanced lifetimes of spin chains coupled to chiral edge states

Delgado

Fernández-Rossier

2019

New J. Phys.

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We consider spin relaxation of finite-size spin chains exchanged coupled with a one-dimensional (1D) electron gas at the edge of a quantum spin Hall (QSH) insulator. Spin lifetimes can be enhanced due to two independent mechanisms. First, the suppression of spin-flip forward scattering inherent in the spin momentum locking of the QSH edges. Second, the reduction of spin-flip backward scattering due to destructive interference of the quasiparticle exchange, modulated by k F d, where d is the inter-spin distance and k F is the Fermi wavenumber of the electron gas. We show that the spin lifetime of the S=1/2 ground state of odd-numbered chains of antiferromagnetically coupled S=1/2 spins can be increased more than 4 orders of magnitude by properly tuning the product k F d and the spin size N, in strong contrast with the 1D case. Possible physical realizations together with some potential issues are also discussed.

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Tuning Edge States in Strained-Layer InAs/GaInSb Quantum Spin Hall Insulators

Cited by 72 publications

References 31 publications

Probing the semiconductor to semimetal transition in InAs/GaSb double quantum wells by magneto-infrared spectroscopy

Probing the semiconductor to semimetal transition in InAs/GaSb double quantum wells by magneto-infrared spectroscopy

Quantum Spin Hall Materials

Enhanced lifetimes of spin chains coupled to chiral edge states

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