Rare-Earth Tetraborides RB${}_4$: Analysis of Trends in the Electronic Structure

Abstract

Both the basic electronic structure of tetraborides, and the changes across the lanthanide series in $R$B${}_4$ ($R$ = rare earth) compounds, are studied using the correlated band theory LDA+U method in the all-electron Full Potential Local Orbital (FPLO) code. A set of boron bonding bands can be identified that are well separated from the antibonding bands. Separately, the ``dimer B'' $2p_z$ orbital is non-bonding ({\it viz.} graphite and MgB${}_2$), and mixes strongly with the metal 4d or $5d$ states that form the conduction states. The bonding bands are not entirely filled even for the trivalent compounds (thus the cation $d$ bands have some filling), which accounts for the lack of stability of this structure when the cations are divalent (with more bonding states unfilled). The trends in the mean $4f$ level for both majority and minority, and occupied and unoccupied, states are presented and interpreted.

10 pages, 9 figures

References in corpus (4)

• Geometrical quadrupolar frustration in DyB${}_4$
• Exchange coupling in Eu monochalcogenides from first principles
• Magnetic Coupling Between Non-Magnetic Ions: Eu3+ in EuN and EuP
• Quadrupolar Frustration in Shastry-Sutherland Lattice of DyB4 Studied by Resonant X-ray Scattering

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• Hysteretic magnetoresistance and unconventional anomalous Hall effect in the frustrated magnet TmB_4
• Origin of modulated phases and magnetic hysteresis in TmB_4
• Columnar antiferromagnetic order and spin supersolid phase on the extended Shastry-Sutherland lattice
• Kondo-Ising and Tight-Binding Models for TmB4
• Ground-state structures in Ising magnets on the Shastry-Sutherland lattice with long-range interactions and fractional magnetization plateaus in TmB4
• Spectral evolution in a Shastry-Sutherland lattice, HoB(4)
• Role of spin-orbit coupling effects in rare-earth metallic tetra-borides : a first principle study
• Phase transition and enhanced hardness of LaB4 under pressure