Host isotope mass effects on the hyperfine interaction of group-V donors in silicon

TL;DR

This study investigates how the mass of silicon isotopes influences the hyperfine interactions of group-V donors in silicon, revealing isotope-dependent spectral splitting and shifts through advanced ENDOR spectroscopy.

Contribution

It demonstrates the isotope mass effects on hyperfine interactions and provides detailed spectral analysis of various group-V donors in isotopically engineered silicon.

Findings

ENDOR lines split into multiple components matching Si isotope distributions

ENDOR components shift linearly with bulk Si isotope mass

Spectral features depend on local isotopic environment

Abstract

The effects of host isotope mass on the hyperfine interaction of group-V donors in silicon are revealed by pulsed electron nuclear double resonance (ENDOR) spectroscopy of isotopically engineered Si single crystals. Each of the hyperfine-split P-31, As-75, Sb-121, Sb-123, and Bi-209 ENDOR lines splits further into multiple components, whose relative intensities accurately match the statistical likelihood of the nine possible average Si masses in the four nearest-neighbor sites due to random occupation by the three stable isotopes Si-28, Si-29, and Si-30. Further investigation with P-31 donors shows that the resolved ENDOR components shift linearly with the bulk-averaged Si mass.