Chaotic quantum transport near the charge neutrality point in inverted type-II InAs/GaSb field-effect transistors

We present here our recent quantum transport results around the charge neutrality point (CNP) in a type-II InAs/GaSb field-effect transistor. At zero magnetic field, a conductance minimum close to 4e(2)/h develops at the CNP and it follows semi-logarithmic temperature dependence. In quantized magnetic (B) fields and at low temperatures, well developed integer quantum Hall states are observed in the electron as well as hole regimes. Charged carrier (electron and hole) transport shows noisy behavior around the CNP at extremely high B fields. When the diagonal conductivity sigma(xx) is plotted against the Hall conductivity sigma(xy), an unexpected conductivity circle law is observed. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4789555]