Electronic structure of TiS2 and its electric transport properties under high pressure

The electronic structure of TiS2 and its transport properties under high pressure have been studied using first-principles calculation and in situ transport parameters measurement. Both the theoretical and experimental results support the conclusion that TiS2 is a semimetal rather than a semiconductor and maintains its semimetallic behavior under high pressure. Although there is no significant change in density of state at Fermi level up to 20 GPa, the transport behavior change drastically at around 15 GPa, manifested by the change in the slope of resistivity and electronic concentration versus pressure curves. This pressure response of transport properties of TiS2 may be associated with conduction of pressure-induced ionization of impurity levels.