Chemical tuning of electrical transport in Ti1−xPtxSe2−y

The structural and transport properties of polycrystalline Ti1−xPtxSe2−y(x≤0.13,y≤0.2) are studied, revealing highly tunable electrical properties, spanning nearly ten orders of magnitude in scaled resistivity. Using x-ray and neutron diffraction, Pt is found to dope on the Ti site. In the absence of Pt doping (for x=0), Se deficiency (y>0) increases the metallic character of TiSe2, while a large increase of the low-temperature resistivity is favored by a lack of Se deficiency (y=0) and increasing amounts of doped Pt (x>0). The chemical tuning of the resistivity in Ti1−xPtxSe2−y with Se deficiency and Pt doping results in a metal-to-insulator transition. Simultaneous Pt doping and Se deficiency (x,y>0) confirms the competition between the two opposing trends in electrical transport, with the main outcome being the suppression of the charge density wave transition below 2 K for y=2x=0.18. Band structure calculations on a subset of Ti1−xPtxSe2−y compositions are in line with the experimental observations