Long spin coherence times in the ground state and an optically excited state of $^{167}$Er$^{3+}$:Y$_2$SiO$_5$ at zero magnetic field

TL;DR

This study demonstrates exceptionally long spin coherence times in erbium-167-doped yttrium orthosilicate at zero magnetic field, highlighting its potential for microwave quantum memory applications.

Contribution

It reports the first measurement of long coherence times in both ground and excited states of erbium-167 in Y$_2$SiO$_5$ at zero magnetic field, surpassing previous results.

Findings

Coherence time of 380 μs in ground state

Coherence time of 1.48 ms in excited state

Longer coherence times than previous zero field measurements

Abstract

Spins in solids are an ideal candidate to act as a memory and interface with superconducting qubits due to their long coherence times. We spectroscopically investigate erbium-167-doped yttrium orthosilicate as a possible microwave-addressed memory employing its microwave frequency transitions that occur without applying an external magnetic field. We obtain coherence times of 380 $\mu$s in a ground state spin transition and 1.48 ms in an excited state spin transition. This is 28 times longer compared to previous zero field measurements, as well as 200 times longer than a previous microwave memory demonstration in the same material. These long coherence times show that erbium-167-doped yttrium orthosilicate has potential as a microwave-addressed quantum memory.