Exchange-induced terahertz minigap in InAs∕GaSb type II and broken-gap quantum wells

We theoretically demonstrate that the exchange effect induced by the carrier-carrier interaction can cause the hybridization of the electron and hole dispersion relations in InAs∕GaSb-based type II and broken-gap quantum well (QW) systems. As a result, a terahertz minigap at the anticrossing points of the conduction and valence bands can be induced by the interlayer electron-hole coupling via the Coulomb interaction. It is shown that the many-body effect is another important source of the hybridization of the dispersion relations in InAs∕GaSb QW systems.