Pressure-induced metallization and superconducting phase in ReS 2

Abstract

Among the family of transition metal dichalcogenides, ReS 2 occupies a special position, which crystalizes in a unique distorted lowsymmetry structure at ambient conditions. The interlayer interaction in ReS 2 is rather weak, thus its bulk properties are similar to those of monolayer. However, how compression changes its structure and electronic properties is unknown so far. Here using ab initio crystal structure searching techniques, we explore the high-pressure phase transitions of ReS 2 extensively and predict two new high-pressure phases. The ambient pressure phase transforms to a "distorted-1T" structure at very low pressure and then to a tetragonal I4 1 /amd structure at around 90 GPa. The "distorted-1T" structure undergoes a semiconductor-metal transition at around 70 GPa with a band overlap mechanism. Electron-phonon calculations suggest that the I4 1 /amd structure is superconducting and has a critical superconducting temperature of about 2 K at 100 GPa. We further perform high-pressure electrical resistance measurements up to 102 GPa. Our experiments confirm the semiconductor-metal transition and the superconducting phase transition of ReS 2 under high pressure. These experimental results are in good agreement with our theoretical predictions.

Strategies on Phase Control in Transition Metal Dichalcogenides

“…Interlayer coupling widely exists in layered TMDs films, which can greatly influence the properties of layered materials . In some special case, interlayer coupling can induce a phase transition in TMDs.…”

Pressure-induced structural and electronic transitions, metallization, and enhanced visible-light responsiveness in layered rhenium disulphide

“…The most common form in TMDs is the H-phase, whereas T-phases are reported to be metastable. However, ReS 2 is an exception, in which the most stable form under ambient condition is a distorted 1T-phase with triclinic symmetry, due to the pronounced Peierls distortion [15][16][17][18][19][20]. Unlike in other TMDs, Peierls distortion of the 1T structure of ReS 2 weakens the coupling interaction, which in turn hinders S-Re-S layers from stacking orderly and minimizes the interlayer overlap of wave-functions to open a band gap (~ 1.4 eV) [15] in the bulk ReS 2 .…”

“…Despite the growing studies on MX 2 , the high-pressure behavior of ReS 2 remains largely unexplored until recently [20,30]. Hou et al reported that ReS 2 undergoes a phase transition at about 10.5 GPa based on x-ray diffraction (XRD) patterns analysis [30].…”

“…Unfortunately, the crystal structure of high pressure phase could not be determined due to insufficient quality of XRD data. This puzzling high-pressure phase was further studied in a theoretical work, which revealed that multilayered ReS 2 would undergo a structural transition to another P-1 phase (denoted as distorted-1T′ hereafter), followed by a sluggish semiconducting to metallic (S-M) transition upon continuous compression [20]. However, the inadequate quality of the experimental diffraction data prevented convincing agreement between experiment and theory.…”

“…More interestingly, there have been growing disputes regarding the claimed direct band gap in bulk ReS 2 in previous studies [15][16][17][18][19][20][21][22]. Recent photoluminescence (PL) and reflectance spectrum experiments at ambient conditions indicated that multilayer ReS 2 possesses an indirect optical gap at 1.40 eV [31].…”