Pressure-induced nontrivial $Z_2$ band topology and superconductivity in transition metal chalcogenide $\mathrm{Ta}_2 \mathrm{Ni}_3 \mathrm{Te}_5$

TL;DR

This study reveals that applying pressure to transition metal chalcogenide Ta2Ni3Te5 induces metallization, a topological phase transition to a nontrivial $Z_2$ state, and superconductivity, highlighting its potential for quantum phenomena exploration.

Contribution

The paper demonstrates pressure-induced topological transition and superconductivity in Ta2Ni3Te5, providing new insights into quantum states in transition metal chalcogenides.

Findings

Metallization at 3.3 GPa

Superconductivity at 21.3 GPa with Tc ~ 0.4 K

Topological phase transition from $Z_2=0$ to $Z_2=1$

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 $Z_2$ band topology and superconductivity in TMC $\mathrm{Ta}_2 \mathrm{Ni}_3 \mathrm{Te}_5$. Our electrical transport measurements show that the metallization emerges at 3.3 GPa, followed by appearance of the superconductivity at $P_{\mathrm{c}}$ = 21.3 GPa with $T_{\mathrm{c}} \sim$ 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 $Z_2=0$ to $Z_2=1$), which occurs after $\mathrm{Ta}_2 \mathrm{Ni}_3 \mathrm{Te}_5$ is turned into an electron-hole compensated semimetal by pressure. The pressure-induced superconductivity at $P_{\mathrm{c}}$ could be attributed to the abruptly enhanced density of states at the Fermi level. These findings demonstrate that $\mathrm{Ta}_2 \mathrm{Ni}_3 \mathrm{Te}_5$ is a new platform for realizing exotic quantum phenomena in TMCs, as well as exploring the interplay between topological property and superconductivity.