Valley-Enabled Intrinsic Dresselhaus Spin-Orbit Coupling in Silicon
Abstract
We develop a symmetry-based theory of spin-orbit-valley coupling in silicon that reveals an intrinsic source of Dresselhaus spin-orbit coupling independent of interfaces or external electric fields. Treating the valley degree of freedom as a symmetry-carrying quantum degree of freedom, we show that the Dresselhaus interaction is necessarily valley off-diagonal and that a bulk contribution proportional to the valley Pauli matrix τ1 is symmetry allowed. Tight-binding calculations yield a bulk coupling more than an order of magnitude larger than typical interface-induced spin-orbit coupling; achieving the same energy scale through the interface-induced mechanism would require electric fields roughly 50 times larger than typical fields. We further derive the symmetry-allowed spin-valley couplings generated by magnetic-field gradients and show how they account for the valley-dependent Zeeman splitting observed in micromagnet experiments. A slight tilt of the background magnetic field out of the plane produces an additional isotropic contribution linear in Bz, providing an experimentally accessible signature of the corresponding coupling constant. Finally, we predict a spin-independent micromagnet-induced valley splitting in the τ3 channel, which is distinct from the τ1,2 channels generated by alloy disorder and therefore remains robust against disorder-induced cancellation. These results establish valley symmetry as a fundamental ingredient in the spin-orbit physics of silicon and provide new mechanisms for controlling and probing spin and valley degrees of freedom in silicon quantum devices.
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BibTeX
@misc{steinschuld2026valleyenabled,
title = {{Valley-Enabled Intrinsic Dresselhaus Spin-Orbit Coupling in Silicon}},
author = {Johannes L. P. Steinschuld and Hendrik J. Bluhm and Lars R. Schreiber and Seyed Akbar Jafari},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.29785},
eprint = {2608.29785},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.29785},
}
RIS
TY - UNPB
TI - Valley-Enabled Intrinsic Dresselhaus Spin-Orbit Coupling in Silicon
AU - Johannes L. P. Steinschuld
AU - Hendrik J. Bluhm
AU - Lars R. Schreiber
AU - Seyed Akbar Jafari
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2608.29785
UR - https://arxiv.org/abs/2608.29785
AB - We develop a symmetry-based theory of spin-orbit-valley coupling in silicon that reveals an intrinsic source of Dresselhaus spin-orbit coupling independent of interfaces or external electric fields. Treating the valley degree of freedom as a symmetry-carrying quantum degree of freedom, we show that the Dresselhaus interaction is necessarily valley off-diagonal and that a bulk contribution proportional to the valley Pauli matrix τ_1 is symmetry allowed. Tight-binding calculations yield a bulk coupling more than an order of magnitude larger than typical interface-induced spin-orbit coupling; achieving the same energy scale through the interface-induced mechanism would require electric fields roughly 50 times larger than typical fields. We further derive the symmetry-allowed spin-valley couplings generated by magnetic-field gradients and show how they account for the valley-dependent Zeeman splitting observed in micromagnet experiments. A slight tilt of the background magnetic field out of the plane produces an additional isotropic contribution linear in B_z, providing an experimentally accessible signature of the corresponding coupling constant. Finally, we predict a spin-independent micromagnet-induced valley splitting in the τ_3 channel, which is distinct from the τ_1,2 channels generated by alloy disorder and therefore remains robust against disorder-induced cancellation. These results establish valley symmetry as a fundamental ingredient in the spin-orbit physics of silicon and provide new mechanisms for controlling and probing spin and valley degrees of freedom in silicon quantum devices.
ER -