Pressure-induced nontrivial Z2 band topology and superconductivity in transition metal chalcogenide Ta2 Ni3 Te5
Abstract
The unique electronic and crystal structures driven by external pressure in transition metal chalcogenides (TMCs) can host emergent quantum states. Here we report pressure-induced metallization, nontrivial Z2 band topology and superconductivity in TMC Ta2 Ni3 Te5. Our electrical transport measurements show that the metallization emerges at 3.3 GPa, followed by appearance of the superconductivity at Pc = 21.3 GPa with Tc 0.4 K. Room-temperature synchrotron x-ray diffraction experiments demonstrate the stability of the pristine orthorhombic structure upon compression. Our first-principles calculations further reveal a topological phase transition (from Z2=0 to Z2=1), which occurs after Ta2 Ni3 Te5 is turned into an electron-hole compensated semimetal by pressure. The pressure-induced superconductivity at Pc could be attributed to the abruptly enhanced density of states at the Fermi level. These findings demonstrate that Ta2 Ni3 Te5 is a new platform for realizing exotic quantum phenomena in TMCs, as well as exploring the interplay between topological property and superconductivity.