Pressure induced semiconductor to metal transition in TmTe

The pressure induced semiconductor to metal transition in the rare earth compound TmTe has been investigated with electrical resistivity measurements under high pressure. At room temperature, the resistivity showed an exponential decrease up to 2 GPa, indicating a linear closing of the energy gap, followed by an almost pressure independent metallic regime. The resistivity in the metallic regime showed a logarithmic temperature dependence reminiscent of a Kondo effect and a TmSe-like anomaly appeared at low temperature and above 5 GPa. At 5.7 GPa the resistivity showed an abrupt decrease that corresponded to the structural phase transition.