Paired Orbitals for Different Spins equations

TL;DR

This paper introduces eigenvalue equations for spin-paired orbitals that serve as an alternative to traditional spin-polarized methods, using biorthogonal orbitals and the Adams-Gilbert approach, especially useful for antiferromagnetic materials.

Contribution

It develops non-canonical unrestricted Hartree-Fock-type equations for different spins using a localizing operator approach, providing a new method for broken-symmetry solutions.

Findings

Derivation of eigenvalue equations for spin-paired orbitals.

Application of Adams-Gilbert localizing operator to derive PODS equations.

Useful for modeling antiferromagnetic materials with broken-symmetry solutions.

Abstract

Eigenvalue-type equations for Lowdin-Amos-Hall spin-paired (corresponding) orbitals are developed to provide an alternative to the standard spin-polarized Hartree-Fock or Kohn-Sham equations. Obtained equations are non-canonical unrestricted Hartree-Fock-type equations in which non-canonical orbitals are fixed to be biorthogonal spin-paired orbitals. To derive paired orbitals for different spins (PODS) equations there has been applied Adams-Gilbert localizing operator approach. PODS equations are especially useful for treatment of the broken-symmetry solutions for antiferromagnetic materials.