Gate induced strain on a two-dimensional hole gas in silicon

We show the effect of gate-induced strain on the valence band of a silicon (Si) metal oxide semiconductor (MOS) confined two-dimensional hole gas (2DHG). Increasing aluminum gate thickness, and thereby the strain in the channel, results in the onset of a second subband contributing to Shubnikov-de Haas oscillations. Temperature-dependent magnetotransport measurements reveal distinct cyclotron masses of $m_c^{\ast }=(0.36\pm 0.04)m_0$ and $m_c^{\ast }=(0.49\pm 0.02)m_0$. The measured cyclotron masses differ from those expected for an idealized heavy-hole (HH)/light-hole (LH) picture, reflecting the combined influence of quantum confinement, strain, and HH-LH mixing on the valence band.