Testing the rSCAN Density Functional for the Thermodynamic Stability of Solids with and without a van der Waals Correction.

A central aim of materials discovery is an accurate and numerically reliable description of thermodynamic properties, such as the enthalpies of formation and decomposition. The rSCAN revision of the strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) balances numerical stability with high general accuracy. To assess the rSCAN description of solid-state thermodynamics, we evaluate the formation and decomposition enthalpies, equilibrium volumes, and fundamental band gaps of more than 1000 solids using rSCAN, SCAN, and PBE, as well as two dispersion-corrected variants, SCAN+rVV10 and rSCAN+rVV10.

Transition Metal Carbo-Chalcogenide "TMCC:" A New Family of 2D Materials.

Here, a new family of 2D transition metal carbo-chalcogenides (TMCCs) is reported, which can be considered a combination of two well-known families, TM carbides (MXenes) and TM dichalcogenides (TMDCs), at the atomic level. Single sheets are successfully obtained from multilayered Nb S C and Ta S C using electrochemical lithiation followed by sonication in water. The parent multilayered TMCCs are synthesized using a simple, scalable solid-state synthesis followed by a topochemical reaction.