Spin transport in non-degenerate Si with a spin MOSFET structure at room temperature

TL;DR

This paper demonstrates room-temperature spin transport in non-degenerate silicon using a spin MOSFET structure, showing gate-controlled modulation of spin signals and long-distance spin transport, advancing silicon-based spintronic devices.

Contribution

First experimental demonstration of gate-modulated spin transport in non-degenerate silicon at room temperature with a spin MOSFET structure.

Findings

Observed spin transport over 20 μm at room temperature.

Demonstrated gate-induced modulation of spin signals.

Identified Elliott-Yafet mechanism as responsible for spin relaxation.

Abstract

Spin transport in non-degenerate semiconductors is expected to pave a way to the creation of spin transistors, spin logic devices and reconfigurable logic circuits, because room temperature (RT) spin transport in Si has already been achieved. However, RT spin transport has been limited to degenerate Si, which makes it difficult to produce spin-based signals because a gate electric field cannot be used to manipulate such signals. Here, we report the experimental demonstration of spin transport in non-degenerate Si with a spin metal-oxide-semiconductor field-effect transistor (MOSFET) structure. We successfully observed the modulation of the Hanle-type spin precession signals, which is a characteristic spin dynamics in non-degenerate semiconductor. We obtained long spin transport of more than 20 {\mu}m and spin rotation, greater than 4{\pi} at RT. We also observed gate-induced modulation of spin transport signals at RT. The modulation of spin diffusion length as a function of a gate voltage was successfully observed, which we attributed to the Elliott-Yafet spin relaxation mechanism. These achievements are expected to make avenues to create of practical Si-based spin MOSFETs.