Singlet-triplet minus mixing and relaxation lifetimes in a double donor dot

TL;DR

This paper reports measurements of singlet-triplet mixing and relaxation lifetimes in a precisely fabricated double phosphorus donor quantum dot, revealing long relaxation times and magnetic field dependence.

Contribution

It provides the first detailed measurement of singlet-triplet mixing and relaxation times in a double donor dot with atomic precision.

Findings

Singlet and triplet-minus states identified via spin readout.

Relaxation times of 12.4 s for singlet and 22.1 s for triplet states.

Relaxation times measured at magnetic field of 2.5 T.

Abstract

We measure singlet-triplet mixing in a precision fabricated double donor dot comprising of 2 and 1 phosphorus atoms separated by $16{\pm}1$ nm. We identify singlet and triplet-minus states by performing sequential independent spin readout of the two electron system and probe its dependence on magnetic field strength. The relaxation of singlet and triplet states are measured to be $12.4{\pm}1.0$ s and $22.1{\pm}1.0$ s respectively at $B_z{=}2.5$ T.