Pressure-induced superconductivity in semimetallic 1T-TiTe₂ and its persistence nature upon decompression

1T-TiTe₂ belongs to the family of layered transition metal dichalcogenide compounds that provide important playground revealing exotic ground state electronic orders by tuning the Fermi surface topology and many body effects, either purely by lowering temperature or carrier doping or external pressure [1,2]. A large Te spin-orbit interaction and enhanced p-d hybridization near Fermi level make its Fermi surfaces more susceptible to external parameters.

We will present the resistance and magnetoresistance data of 1T-TiTe₂ single crystal studied under hydrostatic and uniaxial compressions. While the semimetallic state is retained in nearly hydrostatic pressures, small uniaxial compression drives the system into a charge density wave ordered state, which eventually collapses at higher pressures. Superconductivity emerges at 5 GPa, rapidly increasing to a critical temperature (T_c) of 5.3 K at 13 GPa, irrespective of pressure condition and so the formation of the CDW. Most surprisingly, the superconducting state persists upon complete decompression even as the CDW state reemerges, establishing a novel phase diagram under uniaxial compression.

1. E. Morosan et al., Nature Phys. 2, 544, 2006
2. B. Sipos et al., Nature Mater. 7, 960, 2008