Large gap quantum spin Hall insulator, massless Dirac fermions and bilayer graphene analogue in InAs/Ga(In)Sb heterostructures

摘要

The quantum spin Hall insulator (QSHI) state has been demonstrated in twosemiconductor systems - HgTe/CdTe quantum wells (QWs) and InAs/GaSb QWbilayers. Unlike the HgTe/CdTe QWs, the inverted band gap in InAs/GaSb QWbilayers does not open at the $\Gamma$ point of the Brillouin zone, preventingthe realization of massless Dirac fermions. Here, we propose a new class ofsemiconductor systems based on InAs/Ga(In)Sb multilayers, hosting a QSHI state,a graphene-like phase and a bilayer graphene analogue, depending on their layerthicknesses and geometry. The QSHI gap in the novel structures can reach up to60 meV for realistic design and parameters. This value is twice as high as thethermal energy at room temperature and significantly extends the applicationpotential of III-V semiconductor-based topological devices.