Semiconductor-semimetallic transition in InAs-GaSbheterostructures:Evolution of energy spectrum, optical and kinetic phenomena

摘要

In the vicinity of semiconductor-semimetallic transition of InAs-GaSb coupledquantum wells the energy spectrum undergoes dramatic changes. These changes are analyzedas a function of electron and hole quantum well parameters. Both the direct and indirecthybridization gaps depend on above parameters and on interface coupling. When theoverlap of the bands grows, in addition to widely discussed regular parabolic-like and w-likedispersions for ground valence and conduction subbands, there are more complicated cases:the massless photon-like spectrum, the substantially non-parabolic spectrum E(k) / k4 ofhole subband or electron subband, and also the situation when the hole subband turns into wshape,while the other one still keeps a parabolic-like character. Finally, both subbands appearto be of w-shape known as a ?semimetalic case? .