Effects of hydrostatic pressure on the electrical properties of hexagonal Ge₂Sb₂Te₅: Experimental and theoretical approaches

A combination of experiments and first-principles method calculations has been applied to investigate the influence of the hydrostatic pressure on the electrical properties of the phase-change material hexagonal Ge ₂Sb₂Te₅ (h-GST). Experimentally, it is found that the resistance of h-GST declines monotonically with increasing hydrostatic pressure up to 0.7 GPa. Theoretically, the band-structure calculations revealed that the electronic band gap also decreases with the pressure. The hydrostatic pressure increases the conductivity of h-GST by reducing the electronic band gap. The d E_g/dP obtained from theoretical calculations and the d ln ρ/dP by experimental result are in the same order of magnitude.