Site-Selective Mott Transition in a Quasi-One-Dimensional Vanadate V6O13

TL;DR

This study reveals a site-selective Mott transition in V6O13, where different chains exhibit distinct electronic and magnetic behaviors, advancing understanding of orbital and spin interactions in low-dimensional systems.

Contribution

It uncovers the microscopic mechanism of the transition involving site-selective orbital order and chain-dependent magnetic states in V6O13.

Findings

Site-selective d orbital order in one VO6 chain.

Coexistence of orbital-assisted spin-Peierls and antiferromagnetic states.

Insight into the duality of metallic and insulating behaviors.

Abstract

The microscopic mechanism of the metal-insulator transition is studied by orbital-resolved 51V NMR spectroscopy in a prototype of the quasi-one-dimensional system V6O13. We uncover that the transition involves a site-selective d orbital order lifting twofold orbital degeneracy in one of the two VO6 chains. The other chain leaves paramagnetic moments on the singly occupied dxy orbital across the transition. The two chains respectively stabilize an orbital-assisted spin-Peierls state and an antiferromagnetic long-range order in the ground state. The site-selective Mott transition may be a source of the anomalous metal and the Mott-Peierls duality.