Suppression of axionic charge density wave and onset of superconductivity in the chiral Weyl semimetal Ta2Se8 i

Mu QG, Nenno D, Qi YP, Fan FR, Pei C, Elghazali M, Gooth J, Felser C, Narang P, Medvedev S (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Physical Review Materials American Physical Society

Book Volume: 5

Article Number: 084201

Journal Issue: 8

DOI: 10.1103/PhysRevMaterials.5.084201

Abstract

A Weyl semimetal with strong electron-phonon interaction can show axionic coupling in its insulator state at low temperatures, owing to the formation of a charge density wave (CDW). Such a CDW emerges in the linear-chain-compound Weyl semimetal Ta2Se8I below 263 K, resulting in the appearance of the dynamical condensed-matter axion quasiparticle. In this paper, we demonstrate that the interchain coupling in Ta2Se8I can be varied to suppress the CDW formation with pressure, while retaining the Weyl semimetal phase at high temperatures. Above 17 GPa, the Weyl semimetal phase does not survive, and we induce superconductivity, due to the amorphization of the iodine sublattice. Structurally, the quasi-one-dimensional Ta-Se chains remain intact and provide a channel for superconductivity. We highlight that our results show a near-complete suppression of the gap induced by the axionic charge density wave at pressures inaccessible to previous studies. Including this CDW phase, our experiments and theoretical predictions and analysis reveal the complete phase diagram of Ta2Se8I and its relationship to the nearby superconducting state. The results demonstrate Ta2Se8I to be a distinctively versatile platform for exploring correlated topological states.

Involved external institutions

Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids DE Germany (DE) ShanghaiTech University / 上海科技大学 CN China (CN) Harvard University US United States (USA) (US)

How to cite

APA:

Mu, Q.-G., Nenno, D., Qi, Y.-P., Fan, F.-R., Pei, C., Elghazali, M.,... Medvedev, S. (2021). Suppression of axionic charge density wave and onset of superconductivity in the chiral Weyl semimetal Ta2Se8 i. Physical Review Materials, 5(8). https://doi.org/10.1103/PhysRevMaterials.5.084201

MLA:

Mu, Qing-Ge, et al. "Suppression of axionic charge density wave and onset of superconductivity in the chiral Weyl semimetal Ta2Se8 i." Physical Review Materials 5.8 (2021).

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