Research paperInvestigations of press-induced band gap changes in PbS

- The calculated band gap of PbS closes and reopens under hydrostatic pressure.
- PbS is converted from a direct to an indirect band gap semiconductors under the uniaxial pressure.
- The direct-indirect band gap transition can have a significant effect on many properties of PbS.

We applied the hydrostatic and uniaxial pressure respectively to cubic PbS based on the plane-wave pseudo-potential density functional theory. The calculated results indicate that the band gap of PbS closes and reopens under hydrostatic pressure like a topological crystalline insulator, although it isn't a topological crystalline insulator because the pressure induced phase transition will occur when the hydrostatic pressure increases to about 2.2 GPa in fact. In addition, we find that, unlike the case of hydrostatic pressing, when the uniaxial pressure is applied along [0 0 1] direction, PbS is converted from a direct band gap semiconductor to an indirect band gap semiconductors.

95