Pressure-induced Semimetal-to-Semiconductor Transition in Bismuth

Semimetallic bismuth possesses an unusual electronic structure and an extremely small Fermi surface, which it is predicted can be suppressed to zero size by the application of hydrostatic pressure. We report evidence for a such a semimetal-to-semiconductor transition in single crystal bismuth as measured by transport measurements under pressure, finding that the lowtemperature conductivity (a measure of the carrier density) tends to zero at a pressure of around 25 kbar. We further describe a simple modulation technique for measuring quantum oscillations in low fields without compromising the ability to measure conventional resistivity, applicable to piston cylinder cells.