Correlated increase of ε₂‐ and ε₁‐conductivity energies under strain‐induced metal–insulator transition in n‐Ge(Sb)

Abstract

The essential increase of the activation energies of the both ε 2 -conductivity and ε 1 -conductivity in uniaxially strained highly-doped monocrystalline n-Ge(Sb) was found in the pressure range 0 -2.5 GPa and at temperature 4.2 -70 K. A remarkable increase of the known value of the metal-insulator (MI) transition critical concentration of antimony dopant in germanium was obtained and explained by the electron effective mass increase because of appreciable strain-induced energy bands transformation.

Strain‐induced nonlinear behavior of electron effective mass in degenerately doped n‐Si(P) under high uniaxial pressure X || [111]

“…So, the coefficient of strain-induced nonparabolicity in high uniaxially stressed under X || [111] n-Si(P) can be determined both by the magnitude of uniaxial pressure (since energy splitting of Δ 1 and Δ′ 2 bands δε ∼ X) and level of crystal doping. Obviously, in n-Si highly doped with shallow donors the correlated increase of the ε 2 and ε 1 activation energies should be observed in the range of the strain-induced transition from metallic-to activation-type conductivity by analogy with the case of degenerately doped n-Ge(Sb) uniaxially deformed in the [1] direction [9]. The increase of the ε 2 and ε 1 activation energies takes place as a consequence of the electron effective mass increase (Fig.…”