The structural and transport properties of polycrystalline ${\mathrm{Ti}}_{1\text{−}x}{\mathrm{Pt}}_x{\mathrm{Se}}_{2\text{−}y}(x\le 0.13,y\le 0.2)$ 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 ${\mathrm{TiSe}}_2$, 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 ${\mathrm{Ti}}_{1\text{−}x}{\mathrm{Pt}}_x{\mathrm{Se}}_{2\text{−}y}$ 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 ${\mathrm{Ti}}_{1\text{−}x}{\mathrm{Pt}}_x{\mathrm{Se}}_{2\text{−}y}$ compositions are in line with the experimental observations.

• Received 3 October 2014
• Revised 16 December 2014

DOI:https://doi.org/10.1103/PhysRevB.91.045125