Bismuth in silicon qubits: the role of EPR cancellation resonances

TL;DR

This paper explores the unique EPR cancellation-resonance regime in bismuth-doped silicon, revealing its potential to enhance quantum information processing by reducing decoherence and enabling faster qubit manipulation.

Contribution

It identifies and characterizes a novel EPR cancellation-resonance regime in Si:Bi, demonstrating its implications for spectroscopy and quantum computing.

Findings

Identification of a new EPR cancellation-resonance regime

Experimental validation with X-band EPR spectra

Potential for reduced decoherence and faster qubit control

Abstract

We investigate theoretically and experimentally the electron paramagnetic resonance (EPR) spectra of bismuth doped silicon (Si:Bi) at intermediate magnetic fields, $B \approx 0.05 -0.6$ T. We identify a previously unexplored EPR regime of "cancellation-resonances"- where part of the hyperfine coupling is resonant with the external field-induced splitting. We show this regime has interesting and experimentally accessible consequences for spectroscopy and quantum information applications. These include reduction of decoherence, fast manipulation of the coupled nuclear-electron qubit system and line narrowing in the multi-qubit case. We test our theoretical analysis by comparing with experimental X-band (9.7 GHz) EPR spectra obtained in the intermediate field regime.