CYCLOTRON MASS OF 2-DIMENSIONAL HOLES IN STRAINED-LAYER GAAS IN0.20GA0.80AS/GAAS QUANTUM-WELL STRUCTURES/

We report a systematic study of the effective mass of two-dimensional (2D) holes in a series of ten p-type GaAs/In0.20Ga0.80As/GaAs quantum well structure samples. The 2D hole density and its effective mass (m )are independently determined from Shubnikov-de Haas and cyclotron res onance measurements at 4.2 K. We find the m increases from (0.123 +/- 0.005) m(e) to (0.191 +/- 0.015) m(e) as the 2D hole density is varie d from 0.54 x 10(11)/cm(2) to 8.5 x 10(11)/cm(2). The experimental dat a are described quantitatively in terms of a two-band tight binding mo del using the valence band edge mass and strain-induced valence band s plitting as parameters. (C) 1995 American Institute of Physics.