First principles analysis of spin relaxation in germanium

Germanium is an emerging candidate material for quantum technologies due to its high carrier mobility, strong spin-orbit coupling (SOC), and long spin relaxation times. Existing studies of electronic transport and spin relaxation in Ge have focused on phenomenological models and qualitative understanding. In this talk, we show a first principles study of phonon-limited transport and T1 spin relaxation times for electron and hole carriers in bulk Ge. Our calculations accurately describe the electronic structure and electron-phonon interactions by using hybrid functionals and including SOC via fully-relativistic pseudopotentials. Our computed mobilities, velocity-field curves, and T1 spin relaxation times are in excellent agreement with experiments in the 100 – 350 K temperature range for both electron and hole carriers. We analyze the valley-dependent and phonon mode-dependent scattering processes, and find that the charge transport and spin relaxation are governed by distinct microscopic mechanisms. Our work sheds light on microscopic electron and spin dynamics in Ge, advancing the development of future Ge-based quantum technologies and paving the way for first-principles studies of spin relaxation in semiconductor spin qubits.