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.
@article{arxiv.1407.6792,
title = {Host isotope mass effects on the hyperfine interaction of group-V donors in silicon},
author = {T. Sekiguchi and A. M. Tyryshkin and S. Tojo and E. Abe and R. Mori and H. Riemann and N. V. Abrosimov and P. Becker and H. -J. Pohl and J. W. Ager and E. E. Haller and M. L. W. Thewalt and J. J. L. Morton and S. A. Lyon and K. M. Itoh},
journal= {arXiv preprint arXiv:1407.6792},
year = {2014}
}