study of InAs/Al_0.2Ga_0.8Sb asymmetric, borken gap type-II QW system for the possible flat-bands induced effects

10 nm thick InAs/Al_0.2Ga_0.8Sb asymmetric broken gap(type-II) quantum well system have been investigated for the possible flat-band effects induced on such a system. Electronic dispersion relation E(k) of such a system calculated through sloving 8x8 Kane model hamiltonian considering involved mechanisms (SOC, strain) confirming flat-band parts in E(k) at the finite k values. On the other hand experimental results measuring the effective electron mass turns to be half of the value predicted for an electron mass for InAs (bottom of the band value). THz magneto-photoresponse spectroscopy technique was implemented at lambda values of 118 &163 um using FIR laser with Hall bar sample sits at T=1.4 K to measure effective mass value of the InAs based QW sample. We discuss different cenarios for such a system to clarify our experimental results on this abstract.