Deformation potentials of the semimetal HgTe

It has been demonstrated that the hydrostatic deformation potential C-a of a semimetal can be determined from the pressure dependence of intersubband transitions in superlattices containing the semimetal. By means of an investigation of optical absorption in HgTe/Hg0.3Cd0.7Te superlattices at hydrostatic pressures up to 3 GPa at room temperature the following values have been determined: C-a=-3.69±0.10 eV and a-HgTe-a-CdTe=1.31±0.10 eV, where C and a are the deformation potentials of the conduction and valence bands, respectively. Bulk HgTe normally undergoes a phase transition to the cinnabar structure at 1.3 GPa. However, this phase transition is frustrated in HgTe/Hg0.3Cd0.7Te superlattices and the HgTe layers are superpressed above 1.3 GPa.