Inverse spin-Hall effect in GeSn

Abstract

Due to the long spin lifetime and its optical and electrical properties, GeSn is a promising candidate for the integration of spintronics, photonics, and electronics. Here, we investigate the photoinduced inverse spin-Hall effect in a GeSn alloy with 5% Sn concentration. We generate a spin-polarized electron population at the Γ point of the GeSn conduction band by means of optical orientation, and we detect the inverse spin-Hall effect signal coming from the spin-to-charge conversion in GeSn. We study the dependence of the inverse spin-Hall signal on the kinetic energy of the spin-polarized carriers by varying the energy of the impinging photons in the 0.5–1.5 eV range. We rationalize the experimental data within a diffusion model which explicitly accounts for momentum, energy, and spin relaxation of the spin-polarized hot electrons. At high photon energies, when the spin relaxation is mainly driven by phonon scattering, we extract a spin-Hall angle in GeSn which is more than ten times larger than the one of pure Ge. Moreover, the spin–charge interconversion for electrons lying at the Δ valleys of GeSn results to be ≈4.3 times larger than the one for electrons at L valleys.

Isothermal Heteroepitaxy of Ge1–xSnx Structures for Electronic and Photonic Applications

“…Furthermore, the Ge 1– x Sn x material system is making its way into a diversity of research fields, such as nanoelectronics, thermoelectrics, spintronics, and quantum computing . Due to their strong spin–orbit coupling (SOC), holes in Ge have emerged as one of the most promising spin qubit candidates. , To further enhance the SOC strength, materials with higher atomic numbers are preferred due to larger atomic potential variation, which is achieved by the incorporation of Sn atoms into Ge crystals …”

“…3 Moreover, the previously short-wave infrared range dominated by III-V materials was reached and extended into MIR as demonstrated recently by Ge/Ge 1−x Sn x single pixel imagers on Si. 4 Furthermore, the Ge 1−x Sn x material system is making its way into a diversity of research fields, such as nanoelectronics, 5 thermoelectrics, 6 spintronics, 7 and quantum computing. 8 Due to their strong spin−orbit coupling (SOC), holes in Ge have emerged as one of the most promising spin qubit candidates.…”

“…Furthermore, the Ge 1– x Sn x material system is making its way into a diversity of research fields, such as nanoelectronics, 5 thermoelectrics, 6 spintronics, 7 and quantum computing. 8 Due to their strong spin–orbit coupling (SOC), holes in Ge have emerged as one of the most promising spin qubit candidates.…”