Orbitally relieved magnetic frustration in NaVO2

TL;DR

This study explores how orbital ordering relieves magnetic frustration in NaVO2, leading to magnetic ordering at low temperatures through detailed electronic structure calculations.

Contribution

It reveals the mechanism of orbital ordering relieving magnetic frustration and inducing magnetic order in NaVO2, supported by first-principles calculations.

Findings

Magnetic frustration is relieved by lattice distortion at low temperature.

Orbital ordering drives the transition from frustrated to ordered magnetic state.

Small magnetic moments result from orbital and spin moment compensation.

Abstract

The magnetic properties of NaVO2 are investigated using full-potential linearized augmented plane wave method. We perform calculations for three structures. For the rhombohedral structure at 100 K, the t2g orbitals of V ions are split into upper a1g and lower e'g orbitals by a trigonal distortion of compression. For the monoclinic structure at 91.5 K, the system behaves like a frustrated spin lattice with spatially anisotropic exchange interactions. For another monoclinic structure at 20 K, the magnetic frustration is relieved by a lattice distortion which is driven by a certain orbital ordering, and the long-range magnetic ordering is thus formed. Moreover, the small magnetic moment originates from the compensation oforbital moment for the spin moment.