Cyclotron mass of two-dimensional holes in (100) oriented GaAs/AlGaAs heterostructures

Microwave cyclotron resonance of low-density high-mobility two-dimensional hole gases of different densities in (100) oriented GaAs/AlGaAs heterostructures has been measured at 4.2 K. The measurements show that the hole effective mass depends strongly on the confining potential. For holes in a 20 nm quantum well, the cyclotron mass decreases from 0.48m(e) at density p=6.9x10(10)/cm(2) to 0.29m(e) at p=0.8x10(10)/cm(2). The cyclotron mass for holes confined at a heterojunction is fairly insensitive to the density and has a value of approximately 0.5m(e). (C) 2008 American Institute of Physics.