Landau-Level Hybridization and the Quantum Hall Effect in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">I</mml:mi><mml:mi mathvariant="normal">n</mml:mi><mml:mi mathvariant="normal">A</mml:mi><mml:mi mathvariant="normal">s</mml:mi><mml:mo>/</mml:mo><mml:mo>(</mml:mo><mml:mi mathvariant="normal">A</mml:mi><mml:mi mathvariant="normal">l</mml:mi><mml:mi mathvariant="normal">S</mml:mi><mml:mi mathvariant="normal">b</mml:mi><mml:mo>)</mml:mo><mml:mo>/</mml

Suzuki, K.; Takashina, Kei; Miyashita, S.; Hirayama, Y.

doi:10.1103/physrevlett.93.016803

Cited by 29 publications

(18 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The robustness of helical edge conduction is therefore reduced by disorder in type-II quantum wells, such as InAs/GaSb. We discuss the magnetic-field-induced bulk conduction in terms of Landaulevel hybridization [16] and explain why it is only operative for weakly coupled electron-hole subbands.Our investigation is based on the Bernevig-Hughes-Zhang Hamiltonian for inverted electron-hole bilayers [8,10,17]. In zero magnetic field the Hamiltonian of the clean system takes the form…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…If the inverted electron and hole subbands would be totally uncoupled, then all Landau levels from the valence band would move upwards while all Landau levels from the conduction band would move downwards, resulting in an accumulation of Landau levels inside the zero-field band gap |E| < |M 0 |. Electron-hole coupling hybridizes the Landau levels from the conduction and valence band [16], pushing them out of the gap. In a type-I quantum well only a single pair of Landau levels remains inside the gap [see Fig.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Disorder and magnetic-field-induced breakdown of helical edge conduction in an inverted electron-hole bilayer

Pikulin

Hyart

et al. 2014

Phys. Rev. B

View full text Add to dashboard Cite

We calculate the conductance of a two-dimensional bilayer with inverted electron-hole bands to study the sensitivity of the quantum spin Hall insulator (with helical edge conduction) to the combination of electrostatic disorder and a perpendicular magnetic field. The characteristic breakdown field for helical edge conduction splits into two fields with increasing disorder, a field B c for the transition into a quantum Hall insulator (supporting chiral edge conduction) and a smaller field B c for the transition to bulk conduction in a quasimetallic regime. The spatial separation of the inverted bands, typical for broken-gap InAs/GaSb quantum wells, is essential for the magnetic-field-induced bulk conduction-there is no such regime in HgTe quantum wells. A two-dimensional band insulator can support two types of conducting edge states: counterpropagating (helical) edge states in zero magnetic field and unidirectional (chiral) edge states in a sufficiently strong perpendicular field. These two topologically distinct phases are referred to as a quantum spin Hall (QSH) and quantum Hall (QH) insulator, respectively [1,2]. The physics of the QSH-to-QH transition is governed by band inversion [3][4][5]: The electronlike and holelike subbands near the Fermi level are interchanged in a QSH insulator, so that the band gap in the bulk becomes smaller rather than larger with increasing perpendicular magnetic field [6,7]. The gap closing at a characteristic field B c signals the transition from an inverted QSH gap with helical edge states to a noninverted QH gap supporting chiral edge states.The early experiments on the QSH effect were performed in HgTe layers with CdTe barriers (type-I quantum wells) [8,9]. Recently the effect has also been observed in InAs/GaSb bilayers with AlSb barriers (type-II quantum wells) [10][11][12][13]. Both types of quantum wells can have electron-hole subbands in inverted order, but while these are strongly coupled in type-I quantum wells, they are spatially separated and weakly coupled in the broken-gap quantum wells of type II (see Fig. 1). Although the difference has no consequences in zero magnetic field, we will show here that the breakdown of helical edge conduction in a magnetic field becomes qualitatively different.In both type-I and type-II quantum wells we find an increase with disorder of the characteristic field B c for the QSH-to-QH transition, as a consequence of the same mechanism that is operative in topological Anderson insulators [14]: a disorderinduced renormalization of the band gap [15]. Basically, in a narrow-gap semiconductor the effect of disorder on the bulk band gap is opposite in the inverted and noninverted cases. While a noninverted band gap is reduced by disorder, the inverted band gap is increased. Since B c is proportional to the zero-field band gap, it is pushed to larger fields by impurity scattering.As a consequence, disorder increases the robustness of helical edge conduction in type-I quantum wells, such as HgTe. In contrast, we find that in broken-gap quantum...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Disorder and magnetic-field-induced breakdown of helical edge conduction in an inverted electron-hole bilayer

Pikulin

Hyart

et al. 2014

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…A resistor network model of the device is developed to decouple the edge conductance from the bulk conductance, providing a quantitative technique to further investigate the nature of this trivial edge conductance, conclusively identified here as being of n type. InAs=GaSb double-quantum-well structures have been long known to exhibit semimetallic behavior when the electron energy level in the InAs well lies below the hole energy level in the GaSb well [1][2][3][4][5][6]. In such an "inverted" regime, the material system was predicted to be a topological quantum spin Hall insulator with insulating bulk and conducting helical edge states [7].…”

mentioning

confidence: 99%

Decoupling Edge Versus Bulk Conductance in the Trivial Regime of anInAs/GaSbDouble Quantum Well Using Corbino Ring Geometry

et al. 2016

View full text Add to dashboard Cite

A Corbino ring geometry is utilized to analyze edge and bulk conductance of InAs/GaSb quantum well structures. We show that edge conductance exists in the trivial regime of this theoretically-predicted topological system with a temperature insensitive linear resistivity per unit length in the range of 2 k/m. A resistor network model of the device is developed to decouple the edge conductance from the bulk conductance, providing a quantitative technique to further investigate the nature of this trivial edge conductance, conclusively identified here as being of n-type.

show abstract

“…In the previous works, the electron-hole hybridization in InAs/GaSb broken-gap QWs have been well studied 9,10,26,27 . It was shown that the "spin-up" and the "spin-down" states are affected differently by the hybridization 9,10 .…”

Section: Introductionmentioning

confidence: 99%

Spin states in InAs/AlSb/GaSb semiconductor quantum wells

Yang

Chang

2009

Phys. Rev. B

View full text Add to dashboard Cite

We investigate theoretically the spin states in InAs/AlSb/GaSb broken-gap quantum wells by solving the Kane model and the Poisson equation self-consistently. The spin states in InAs/AlSb/GaSb quantum wells are quite different from those obtained by the single-band Rashba model due to the electron-hole hybridization. The Rashba spin-splitting of the lowest conduction subband shows an oscillating behavior. The D'yakonov-Perel' spin relaxation time shows several peaks with increasing the Fermi wavevector. By inserting an AlSb barrier between the InAs and GaSb layers, the hybridization can be greatly reduced. Consequently, the spin orientation, the spin splitting, and the D'yakonov-Perel' spin relaxation time can be tuned significantly by changing the thickness of the AlSb barrier.

show abstract

Landau-Level Hybridization and the Quantum Hall Effect inInAs/(AlSb)/

Cited by 29 publications

References 16 publications

Disorder and magnetic-field-induced breakdown of helical edge conduction in an inverted electron-hole bilayer

Disorder and magnetic-field-induced breakdown of helical edge conduction in an inverted electron-hole bilayer

Decoupling Edge Versus Bulk Conductance in the Trivial Regime of anInAs/GaSbDouble Quantum Well Using Corbino Ring Geometry

Spin states in InAs/AlSb/GaSb semiconductor quantum wells

Contact Info

Product

Resources

About