Electron <i>g</i>-factor of Ge strained by a SiGe substrate and its dependence on growth directions

Abstract We propose a Ge hole system in a strained Ge/SiGe quantum well with a diamond structure as a suitable platform for photon-spin conversion for its potential for high-performance spin qubits and optical transitions at telecom wavelengths. A critical condition of photon-hole spin transduction is that the g -factor of the electron at the Γ point must be much larger than that of the hole. We calculated the electron g -factor in strained Ge, examining its dependence on both the growth direction ([100], [110], and [111]) and the Ge content of the SiGe substrate by using an eight-band model. Our results show that the absolute value of the electron g -factor decreases as Ge content decreases, ranging from approximately 2.88 to 2.00 across all growth directions. This indicates that the system is suitable for coherent photon-spin transduction.