Intrinsic Insulating Ground State in Transition Metal Dichalcogenide TiSe2

Orateur : Daniel CAMPBELL (Maryland University, USA)

TiSe2 is a member of the transition metal dichalcogenide (TMD) family that, like many other TMDs, possesses a charge-ordered ground state. Due to weak interlayer bonding, there are various ways to suppress the charge density wave transition, vary low temperature resistivity by orders of magnitude, or stabilize magnetic or superconducting states. This seminar will present the results of a new synthesis method whereby crystals were grown in an argon gas environment at elevated pressures of up to 180 bar. Above 100 K, properties are unchanged from the standard chemical vapor transport technique. However, a hysteretic, insulating transition beginning around 80 K is distinct from anything previously observed, and suggests that pressure growth may finally allow access to a nonmetallic ground state in a material long speculated to be an excitonic insulator.

Télécharger dans mon agenda