Intrinsic Insulating Ground State in Transition Metal Dichalcogenide TiSe₂

TiSe₂ has received significant research attention over the past four decades, in large part due to the uniqueness of its charge-ordered state. Different techniques can suppress the charge density wave transition, vary low temperature resistivity by orders of magnitude, and stabilize magnetic or superconducting states. This talk will present the results of a new synthesis method whereby samples were grown in an argon gas environment at elevated pressures up to 180 bar. Above 100 K, properties (including those of the 200 K CDW) are unchanged from prior reports. However, a hysteretic resistance region beginning around 80 K, accompanied by insulating low temperature behavior, is distinct from anything previously observed. This new feature suggests that pressure growth may allow access to a nonmetallic ground state in a material long speculated to be an excitonic insulator.