Anderson-Mott Transition in Elemental Tellurium under pressure*

Elemental tellurium is a small band-gap which is always p-doped. Under hydrostatic pressure, the band gap narrows, and it has been suggested that below its crystal phase transition at 40 kbar, the gap might close, leading to a transition to a non-trivial state. We show that a high quality elemental tellurium single crystal undergoes a quantum phase transitions at low temperature from an Anderson insulator to a disordered metal around 17 kbar. The critical exponents are consistent with a scenario in which the often-discussed pressure induced Lifshitz transition shifts the Fermi level to a position below the mobility edge. Previous experiments with different results can be linked and explained with the possibility of an Anderson-Mott ground state and the observed quantum phase transition at 17 kbar.