Anomalous magnetoresistance and band crossing in uniaxially compressed HgTe

Resistivity at helium temperatures of uniaxially compressed slightly p‐type HgTe decreases greatly by application of a magnetic field along the stress direction. It increases again above a certain magnetic field HM showing a large resistance minimum. The minimum position HM increases proportionally to the applied compression. These properties are investigated using a magnetic field up to 55 kOe under a uniaxial compression up to about 7 × 108 dyn/cm2. By comparison with the magnetic sub‐band scheme calculated by the effective mass theory, it is concluded that the resistance minimum is due to a band‐crossing HM between the lowest Landau levels of the conduction and the valence bands. A second band‐crossing point is also observed by using a magnetic field modulation technique. A shear deformation potential constant of the Γ8‐band b is deduced; b = (−1.5 ± 0.2) eV. Further, an acceptor impurity band in the stress‐induced band gap is found by the analysis of the temperature dependence of weak field Hall coefficient.