# Suppression of 1/f noise in solid state quantum devices by surface spin desorption

## TL;DR

This study demonstrates that removing surface spins from solid state quantum devices significantly reduces 1/f noise, improving device coherence by linking magnetic surface states to dielectric noise.

## Contribution

It provides experimental evidence that surface spin desorption reduces noise and identifies the chemical nature of magnetic moments affecting quantum device performance.

## Key findings

- Desorption of surface spins reduces frequency noise by nearly tenfold.
- Surface spins are chemically characterized as magnetic adsorbates.
- Coupling between surface spins and resonator electric fields causes dielectric noise.

## Abstract

Noise and decoherence due to spurious two-level systems (TLS) located at material interfaces is a long-standing issue in solid state quantum technologies. Efforts to mitigate the effects of TLS have been hampered by a lack of surface analysis tools sensitive enough to identify their chemical and physical nature. Here we measure the dielectric loss, frequency noise and electron spin resonance (ESR) spectrum in superconducting resonators and demonstrate that desorption of surface spins is accompanied by an almost tenfold reduction in the frequency noise. We provide experimental evidence that simultaneously reveals the chemical signatures of adsorbed magnetic moments and demonstrates their coupling via the electric-field degree of freedom to the resonator, causing dielectric (charge) noise in solid state quantum devices.