Electronic and magnetic properties of new binary uranium-boron compounds with 2D and 3D boron networks: A revisit of the U:B system

TL;DR

This study uses density functional theory to explore the electronic and magnetic properties of newly identified uranium-boron compounds with 2D and 3D boron networks, revealing a structural crossover and magnetic behaviors.

Contribution

It introduces additional uranium-boron compounds with complex boron networks and analyzes their stability, electronic structure, and magnetic properties using DFT calculations.

Findings

Identification of stable UB3 and UB6 compounds with magnetic ground states

Observation of a structural crossover from 2D to 3D boron networks

Magnetic moments of 1.47 and 2.40 Bohr magnetons for UB3 and UB6

Abstract

Based on crystal chemistry rationale and calculations within the density functional theory DFT, the U:B system is complemented with additional binary compounds UB3, U2B6, and UB6 possessing two-dimensional 2D and 3D boron substructures. Observations are supported quantitatively with the trends of cohesive energies, charge transfers onto the boron sub-lattice and geometry optimized structures. The results point out to a structure crossover from hexagonal (layer B network) to 3D boron network at compositions above UB3 found to be connected with a threshold amount of charge onto boron which is ~0.46. From the energy-volume of states EOS considering spin degenerate and spin-polarized configurations, hexagonal UB3, and cubic UB6 were found in a stable ferromagnetic ground state with 1.47 and 2.40Bohr Magnetons spin-only moments. The volume variations of magnetization show respectively a smooth and abrupt evolution for UB3 and UB6.