Strain-induced heavy-hole-to-light-hole energy splitting in (111)B pseudomorphic ${\mathrm{In}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$As quantum wells

Experimental investigation of the energy-band structure of (111)B and (100) ${\mathrm{In}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$As quantum wells demonstrates that the strain-induced heavy-hole to light-hole energy splitting is considerably larger for (111)B pseudomorphic layers than for otherwise identical (100) structures. In general, the measured energy splittings, for both orientations, agree well with a simple one-band envelope-function model that includes strain corrections. However, for (111)B ${\mathrm{In}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$As quantum wells with y≥0.072, there is evidence of a smaller hydrostatic strain component than is predicted by theory.