Structural and High-Pressure Properties of Rheniite (ReS2) and (Re,Mo)S2

Abstract

Rhenium disulfide (ReS2), known in nature as the mineral rheniite, is a very interesting compound owing to its remarkable fundamental properties and great potential to develop novel device applications. Here we perform density functional theory (DFT) calculations to investigate the structural properties and compression behavior of this compound and also of the (Re,Mo)S2 solid solution as a function of Re/Mo content. Our theoretical analysis is complemented with high-pressure X-ray diffraction (XRD) measurements, which have allowed us to reevaluate the phase transition pressure and equation of state of 1T-ReS2. We have observed the 1T-to-1T’ phase transition at pressures as low as ~2 GPa, and we have obtained an experimental bulk modulus, B0, equal to 46(2) GPa. This value is in good agreement with PBE+D3 calculations, thus confirming the ability of this functional to model the compression behavior of layered transition metal dichalcogenides, provided that van der Waals corrections are taken into account. Our experimental data and analysis confirm the important role played by van der Waals effects in the high-pressure properties of 1T-ReS2.

Experimental and Theoretical Studies of the Electronic Band Structure of Bulk and Atomically Thin Mo1–xWxSe2 Alloys

“…Moreover, the mentioned PR signal assignment to transitions between bands was performed, taking into account their spin-layer polarization. ,, To determine the theoretical parameters, we have calculated the electronic band structure of the Mo 1– x W x Se 2 alloy, with different W contents, as described in the Computational Methods section. The used here D3 vdW correction that is relevant for layered crystals, together with the mBJ-TB09 potential, has been shown to work successfully for TMDs. ,,, Furthermore, to reproduce the random distribution of cation (metal) atoms on crystal sites, we used the SQS approach as it was effectively applied to study semiconductor alloys. ,,− The calculated electronic band structures of MoSe 2 and WSe 2 are presented on the top panel of Figure . We consider here primarily the lowest/highest energetically located conduction/valence bands labeled by c / v letters.…”

Study and Analysis on the Influence Degree of Particle Settlement Factors in Pipe Transportation of Backfill Slurry

“…In this study, ultrafine unclassified tailings were used as the experimental material, whereas the weighted mean particle size was 15.05 µm. Both the apparent and bulk densities are approximately the same [39][40][41][42]. Experimental materials were treated with extremely fine and approximately uniform shapes.…”

Crystal Structure Prediction and Lattice Dynamical Calculations for the Rare Platinum-Group Mineral Zaccariniite (RhNiAs)

“…However, it is well known that LDA fails to reproduce the pressure behavior of materials whose fundamental properties are strongly determined by vdW interactions. This is the case, for instance, for the vibrational properties of layered transition metal dichalcogenides (TMDCs), such as MoS 2 , HfS 2 , and ReS 2 [25,26]. For these materials, it is found that PBE calculations do properly describe their highpressure lattice dynamical properties, provided that vdW corrections are considered.…”

“…This is due to the fact that, as can be observed after diagonalization of the dynamical matrix for the zone-center phonons, the low-frequency B 1g mode involves atomic displacements along the x-y plane, with the Ni and As layers oscillating in phase, and 180 • out of phase, relative to the Rh layers. As occurs in layered materials, such as TMDCs, these types of vibrations are strongly dependent on vdW forces [25,26], and, as a consequence of this, no reliable results were obtained for this mode when the lattice dynamical calculations were performed neglecting vdW effects. In other words, it is essential to include vdW corrections to calculate the phonon properties of layered materials, such as RhNiAs.…”