Uncovering 0D and 1D Electrides with Low Work Function in a Sc–P System

Abstract

Electrides have drawn much interest in recent years due to their high carrier mobility, low work function, and exotic catalytic performance. Inspired by the discovery of diverse high pressure electrides, here we investigated the potential electrides in the Sc−P system under high pressure. Through extensively unbiased structure searches, Sc 5 P 3 _P6 3 /mcm was newly found to be robustly stable at ambient and high pressure, whereas ScP 3 _Pmc2 1 , ScP 2 _C2/m, ScP_R-3m, Sc 2 P_Cmce, Sc 2 P_P6 3 /m, and Sc 3 P_Pm-3m were found to be stable under high pressure. Atomic-scale voids in Sc6 octahedra are formed in Sc 5 P 3 _P6 3 /mcm, Sc 3 P_Pm-3m, and Sc 3 P_Pnma. By analyzing the electronic structure, high electron accumulations can be observed in the voids, which act as anionic electrons. Especially, Sc 5 P 3 _P6 3 /mcm is verified to be 1D electride, with anionic electrons confined in the channel voids along the z axis, while Sc 3 P_Pm-3m and Sc 3 P_Pnma are 0D electrides. The calculated lowest work functions of Sc 5 P 3 _P6 3 /mcm and Sc 3 P_Pm-3m are 2.64 and 2.57 eV, respectively, comparable to those of Ca 2 N and LaScSi. The low work function and special stability suggest that they are potential materials in electron emitters and catalyst applications.

BaCu, a Two-Dimensional Electride with Cu Anions

“…The structure optimization and electronic structure calculations for BaCu were performed using the VASP software package based on density functional theory. , The generalized gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) functional and the projector augmented plane wave (PAW) method were used for the first-principles calculations. , The van der Waals density functional (vdW-DF) of optB86b was applied during the calculations . The plane-wave cutoff energy is 600 eV, and a Monkhorst–Pack k -point grid of 2π × 0.03 Å –1 was used.…”