Band-edge properties of a semiconductor alloy: An NMR study of Hg1−xCdxTe
Abstract
We report Hg199 NMR measurements of narrow-gap Hg1−xCdxTe alloys in the range x=0.20–0.28. By studying temperature dependences, we have identified intrinsic Knight shifts in these alloys. This provides a measure of Hg orbital contributions to conduction-electron states, and we find a consistently strong average contribution from Hg s orbitals. Furthermore, we identify local variations in the Knight shift with spatial variations in conduction-electron densities and symmetries. These characteristics have been related to randomly populated sites within the alloys. We also discuss Hg199 chemical shifts and their relation to local orbital charges.