Charge-noise induced dephasing in silicon hole-spin qubits

TL;DR

This paper theoretically analyzes charge-noise induced dephasing in silicon hole-spin qubits, revealing device-dependent sweet-spots that significantly enhance coherence times, reaching milliseconds.

Contribution

It introduces higher-order corrections to the Luttinger Hamiltonian and identifies conditions for dephasing sweet-spots in silicon hole-spin qubits.

Findings

Sweet-spots for dephasing are sensitive to device parameters.

Dephasing times can be increased to milliseconds at sweet-spots.

Higher-order Hamiltonian corrections are crucial for accurate modeling.

Abstract

We investigate theoretically charge-noise induced spin dephasing of a hole confined in a quasi-two-dimensional silicon quantum dot. Central to our treatment is accounting for higher-order corrections to the Luttinger Hamiltonian. Using experimentally reported parameters, we find that the new terms give rise to sweet-spots for the hole-spin dephasing, which are sensitive to device details: dot size and asymmetry, growth direction, and applied magnetic and electric fields. Furthermore, we estimate that the dephasing time at the sweet-spots is boosted by several orders of magnitude, up to order of milliseconds.