Disorder and magnetic-field induced breakdown of helical edge conduction   in an inverted electron-hole bilayer
  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 quasi-metallic 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. 
D. I. Pikulin, T. Hyart, Shuo Mi, J. Tworzyd{\l}o, M. Wimmer, and C.   W. J. Beenakker
cond-mat.mes-hall cond-mat.dis-nn