Electronic structure, phase stability, and semimetal-semiconductor transitions in Bi

The structural stability of bulk Bi is studied using the local-density full-potential linear muffin-tin orbital method. The effect of both the trigonal shear angle and internal displacement on the electronic structure is determined. It is shown that the internal displacement changes the Bi electronic structure from a metal to a semimetal, in qualitative agreement with a Jones-Peierls-type transition. The total energy is calculated to have a double-well dependence on the internal displacement, and to provide a stabilization of the trigonal phase. We show that an increase of trigonal shear angle (towards the cubic value of 60°) leads to a semimetal-semiconductor transition in Bi. Using coherency strain arising from a film/substrate lattice constant mismatch, this may provide a way to induce semiconducting behavior in Bi films, and with it to control their thermoelectric properties.