Quantum Spin Hall Insulator State in HgTe Quantum Wells

@article{Knig2007QuantumSH,
  title={Quantum Spin Hall Insulator State in HgTe Quantum Wells},
  author={Markus K{\"o}nig and Steffen Wiedmann and Christoph Br{\"u}ne and Andreas Roth and Hartmut Buhmann and Laurens W. Molenkamp and Xiao-liang Qi and Shou-Cheng Zhang},
  journal={Science},
  year={2007},
  volume={318},
  pages={766 - 770}
}
Recent theory predicted that the quantum spin Hall effect, a fundamentally new quantum state of matter that exists at zero external magnetic field, may be realized in HgTe/(Hg,Cd)Te quantum wells. We fabricated such sample structures with low density and high mobility in which we could tune, through an external gate voltage, the carrier conduction from n-type to p-type, passing through an insulating regime. For thin quantum wells with well width d < 6.3 nanometers, the insulating regime showed… 
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References

SHOWING 1-10 OF 46 REFERENCES
Experimental observation of the quantum Hall effect and Berry's phase in graphene
TLDR
An experimental investigation of magneto-transport in a high-mobility single layer of graphene observes an unusual half-integer quantum Hall effect for both electron and hole carriers in graphene.
Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
We show that the quantum spin Hall (QSH) effect, a state of matter with topological properties distinct from those of conventional insulators, can be realized in mercury telluride–cadmium telluride
Quantum spin Hall effect.
TLDR
This work predicts a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of 2(e/4pi).
Spin-Hall insulator.
TLDR
This work theoretically predicts the dissipationless spin-Hall effect, without any accompanying charge current, in some classes of band insulators, including zero-gap semiconductors such as HgTe and narrow-gap SOCs such as PbTe, and is the first example of a nontrivial topological structure in a band insulator without any magnetic field.
Dissipationless Quantum Spin Current at Room Temperature
Although microscopic laws of physics are invariant under the reversal of the arrow of time, the transport of energy and information in most devices is an irreversible process. It is this
Gate control of the giant Rashba effect in HgTe quantum wells
HgTe/Hg0.3Cd0.7Te(0 0 1) quantum well structures fabricated with a Si–O–N insulator layer and an Au top gate electrode exhibit hysteresis effects in their gate-voltage dependent carrier density and
Experimental observation of the spin-Hall effect in a two-dimensional spin-orbit coupled semiconductor system.
TLDR
The experimental observation of the spin-Hall effect in a 2D hole system with spin-orbit coupling shows only a weak effect of disorder, suggesting that the clean limitspin-Hall conductance description (intrinsic spin- hall effect) might apply to this system.
Two-dimensional gas of massless Dirac fermions in graphene
TLDR
This study reports an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation and reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions.
Stability of the quantum spin Hall effect: Effects of interactions, disorder, and Z 2 topology
The stability to interactions and disorder of the quantum spin Hall effect (QSHE) proposed for time-reversal-invariant 2D systems is discussed. The QSHE requires an energy gap in the bulk and gapless
Z2 topological order and the quantum spin Hall effect.
TLDR
The Z2 order of the QSH phase is established in the two band model of graphene and a generalization of the formalism applicable to multiband and interacting systems is proposed.
...
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