Quasi-two-dimensional superconductivity from dimerization of atomically ordered AuTe<sub>2</sub>Se<sub>4/3</sub> cubes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29021625.
- Also identified by DOI 10.1038/s41467-017-00947-0 and PMC identifier 5636790.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The emergent phenomena such as superconductivity and topological phase transitions can be observed in strict two-dimensional (2D) crystalline matters. Artificial interfaces and one atomic thickness layers are typical 2D materials of this kind. Although having 2D characters, most bulky layered compounds, however, do not possess these striking properties. Here, we report quasi-2D superconductivity in bulky AuTe<sub>2</sub>Se<sub>4/3</sub>, where the reduction in dimensionality is achieved through inducing the elongated covalent Te-Te bonds. The atomic-resolution images reveal that the Au, Te, and Se are atomically ordered in a cube, among which are Te-Te bonds of 3.18 and 3.28 Å. The superconductivity at 2.85 K is discovered, which is unraveled to be the quasi-2D nature owing to the Berezinsky-Kosterlitz-Thouless topological transition. The nesting of nearly parallel Fermi sheets could give rise to strong electron-phonon coupling. It is proposed that further depleting the thickness could result in more topologically-related phenomena.Emergent phenomena often appear in crystals in the two-dimensional limit but are rare in bulky compounds. Here, Guo et al. report a quasi-two-dimensional superconductivity in a bulk material AuTe<sub>2</sub>Se<sub>4/3</sub> at 2.85 K, potentially owing to a topological transition.