Induced spin-orbit coupling in silicon thin films by bismuth doping

TL;DR

This paper demonstrates that doping silicon thin films with bismuth significantly enhances spin-orbit coupling, enabling tunable spin properties crucial for spintronic applications.

Contribution

The study provides experimental evidence that heavy metal doping, specifically with bismuth, can effectively increase and tune the spin-orbit coupling in silicon thin films.

Findings

Bi doping changes magnetoconductance from weak localization to crossover with weak antilocalization.

The spin-orbit coupling length becomes comparable to the phase coherence length at 2 K.

Spin-orbit coupling in Si can be controlled via heavy metal doping.

Abstract

We demonstrate an enhancement of the spin-orbit coupling in silicon (Si) thin films by doping with bismuth (Bi), a heavy metal, using ion implantation. Quantum corrections to conductance at low temperature in phosphorous-doped Si before and after Bi implantation is measured to probe the increase of the spin-orbit coupling, and a clear modification of magnetoconductance signals is observed: Bi doping changes magnetoconductance from weak localization to the crossover between weak localization and weak antilocalization. The elastic diffusion length, phase coherence length and spin-orbit coupling length in Si with and without Bi implantation are estimated, and the spin-orbit coupling length after the Bi doping becomes the same order of magnitude (Lso = 54 nm) with the phase coherence length (L{\phi} = 35 nm) at 2 K. This is an experimental proof that the spin-orbit coupling strength in Si thin film is tunable by doping with heavy metals.