On a Simplified Analysis of the Effective Electron Mass in Ultrathin Films of Nonparabolic Semiconductors in the Presence of a Parallel Magnetic Field

An attempt is made to study the effective electron mass at the Fermi level in ultrathin films of nonparabolic semiconductors in the presence of a parallel magnetic field on the basis of a newly derived electron dispersion law. It is found, taking n-Hg_1−xCd_xTe and In_1−xGa_xAs_xP_1−y lattice matched to InP as examples, that the effective Fermi level mass depends on the subband index in addition to the Fermi energy due to the presence of the magnetic field. The effective masses corresponding to different subbands increase with increasing surface electron concentration and decreasing film thickness. Besides, thc numerical values of the masses in quaternary alloys are smaller than those for ternary semiconductors. In addition, the corresponding well-known results of ultrathin films of nonparabolic Semiconductors in the absence of the magnetic field are also obtained as special cases of our generalized formulation under certain limiting conditions.