Probing high mobility, spin polarised holes via terahertz spectroscopy

Abstrakt: Solid-⁠state systems with exotic and controllable spin order are being explored as materials for spintronic devices. In this talk I will highlight our recent work on probing spin-⁠orbit coupling in a non-⁠contact manner via terahertz time-⁠domain magneto-⁠spectroscopy of heavy holes in strained germanium quantum wells. I will discuss how strain and asymmetric modulation doping can create a high-⁠mobility 2D heavy-⁠hole gas that remains spin-⁠polarised even to zero magnetic field, via the Rashba interaction, and how this can be probed via terahertz spectroscopy. I will also describe how this high mobility system exhibits the a.c. analogue of the quantum Hall effect even at terahertz frequencies. This suggests the promise of this system for fundamental physical studies as well as in CMOS-⁠compatible electronics.