Orbitally Driven Spin Pairing in the 3D Non-Magnetic Mott Insulator BaVS3: Evidence from Single Crystal Studies

TL;DR

This study investigates BaVS3, revealing orbital ordering and spin pairing phenomena through single crystal measurements, highlighting phase transitions and the nature of its insulating state.

Contribution

It provides experimental evidence for orbitally driven spin pairing and orbital ordering in BaVS3, a non-magnetic Mott insulator, using detailed single crystal studies.

Findings

Anomaly in magnetic anisotropy at T_X indicates a phase transition.

Resistivity is nearly isotropic in both metallic and insulating states.

The low-temperature phase involves orbital ordering and spin pairing.

Abstract

Static electrical and magnetic properties of single crystal BaVS_3 were measured over the structural (T_S=240K), metal-insulator (T_MI=69K), and suspected orbital ordering (T_X=30K) transitions. The resistivity is almost isotropic both in the metallic and insulating states. An anomaly in the magnetic anisotropy at T_X signals a phase transition to an ordered low-T state. The results are interpreted in terms of orbital ordering and spin pairing within the lowest crystal field quasi-doublet. The disordered insulator at T_X<T<T_MI is described as a classical liquid of non-magnetic pairs.