3 research outputs found
Electric field driven quantum phase transition between band insulator and topological insulator
We demonstrate theoretically that electric field can drive a quantum phase
transition between band insulator to topological insulator in CdTe/HgCdTe/CdTe
quantum wells. The numerical results suggest that the electric field could be
used as a switch to turn on or off the topological insulator phase, and
temperature can affect significantly the phase diagram for different gate
voltage and compositions. Our theoretical results provide us an efficient way
to manipulate the quantum phase of HgTe quantum wells.Comment: 4 pages, 4 figure
D'yakonov-Perel' spin relaxation in InSb/AlInSb quantum wells
We investigate theoretically the D'yakonov-Perel' spin relaxation time by
solving the eight-band Kane model and Poisson equation self-consistently. Our
results show distinct behavior with the single-band model due to the anomalous
spin-orbit interactions in narrow band-gap semiconductors, and agree well with
the experiment values reported in recent experiment (K. L. Litvinenko, et al.,
New J. Phys. \textbf{8}, 49 (2006)). We find a strong resonant enhancement of
the spin relaxation time appears for spin align along [] at a
certain electron density at 4 K. This resonant peak is smeared out with
increasing the temperature.Comment: 4 pages, 4 figure
Anomalous Rashba spin-orbit interaction in InAs/GaSb quantum wells
We theoretically investigate the Rashba spin-orbit interaction in InAs/GaSb quantum wells (QWs). We find that the Rashba spin-splitting (RSS) sensitively depends on the thickness of the InAs layer. The RSS exhibits nonlinear behavior for narrow InAs/GaSb QWs and the oscillating feature for wide InAs/GaSb QWs. The nonlinear and oscillating behaviors arise from the weakened and enhanced interband coupling. The RSS also show asymmetric features respect to the direction of the external electric field. (C) 2008 American Institute of Physics