Observation of topological surface states and pressure-induced superconductivity in the Van der Waals crystal ZrTiTe4

Abstract

Tuning superconductivity in topological materials has been identified as a promising pathway for achieving topological superconductivity, which could accelerate advancements in topological quantum computation. Ternary transition-metal chalcogenides ABX4 (where A/B = Zr, Hf, or Ti; X = Te) have been theoretically predicted to be candidates for two-dimensional (2D) topological insulators. In this study we systematically investigate the crystal structure, electronic band properties, and pressure effects of one member of this family, namely, ZrTiTe4. Our single-crystal x-ray diffraction studies reveal that ZrTiTe4 adopts a trigonal structure with space group P3¯m1 (no. 164), rather than the previously reported monoclinic (P2/m) structure. Band structure calculations, complemented by angle-resolved photoemission spectroscopy measurements, indicate that ZrTiTe4 exhibits a topological semimetal nature. Notably, the application of high pressure induces superconductivity, with a maximum transition temperature (Tc) of approximately 5.6 K at pressures around 11–14 GPa. Intriguingly, in the optimal pressure region of the dome-shaped phase diagram, the normal-state resistance shows the highest values, and a nearly linear temperature dependence of resistance is observed above Tc. Overall, our results establish the ABX4 family as a promising candidate for exploring the interaction between the nontrivial band topology and superconductivity.

Source-reported materials — not catalogue approval

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