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

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 31P, As75, Sb121, Sb123, and Bi209 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 Si28, Si29, and Si30. Further investigation with 31P donors shows that the resolved ENDOR components shift linearly with the bulk-averaged Si mass.