Effect of Strain on Room-Temperature Spin Transport in Si0.1Ge0.9

Abstract

We report a strain effect on spin transport in semiconductors that exhibit $\mathrm{Ge}$-like conduction bands at room temperature. Using four-terminal nonlocal spin-transport measurements in lateral spin-valve devices, we experimentally estimate the spin diffusion length ($\ensuremath{\lambda}$) of $\mathrm{Ge}$ and strained ${\mathrm{Si}}_{0.1}{\mathrm{Ge}}_{0.9}$ with two different carrier concentrations. Despite the $\mathrm{Ge}$-like electronic band structure, the obtained $\ensuremath{\lambda}$ of a strained ${\mathrm{Si}}_{0.1}{\mathrm{Ge}}_{0.9}$ is comparable to that of a $\mathrm{Si}$ channel. We discuss a possible mechanism of the strain-induced enhancement of $\ensuremath{\lambda}$ at room temperature. As a consequence, we demonstrate the electrical detection of 5-$\ensuremath{\mu}\mathrm{m}$ lateral spin transport in the strained ${\mathrm{Si}}_{0.1}{\mathrm{Ge}}_{0.9}$ by applying an electric field at room temperature.