Electronic properties of hfte₂

We report measurements of the transport properties of HfTe₂and find these to be characteristic of a semimetal. We consider that this semimetallic behaviour arises from a small overlap of the tellurium p valence band and the hafnium d conduction band and estimate a band overlap of about 0.3 eV. Measurements of the conductivity and Hall coefficient show an increase in the band overlap and carrier concentration with pressure. Although there are some anomalies in the low-temperature transport properties at ambient pressure, we can find no evidence from either x-ray or electron diffraction for any associated structural phase transition such as that found in TiSe₂. However, at pressures above 45 kbar there is a slow transition to a higher-resistivity phase.