Resonating Valence Bond States in 2 and 3D: Brief History and Recent Examples

TL;DR

This paper reviews the history of Resonating Valence Bond (RVB) states and presents recent theoretical developments and examples of RVB states in 2D and 3D materials, highlighting their potential realization in various synthesized systems.

Contribution

It offers a concise history of RVB states and introduces recent theoretical models and examples of RVB states in new materials like doped diamond, xcob, organic conductors, and graphene.

Findings

RVB states can be stabilized in 2D and 3D materials under certain conditions.

Recent synthesis of materials exhibiting RVB states has been achieved.

Theoretical models predict RVB behavior in several novel compounds.

Abstract

Resonating Valence Bond states are quantum spin liquids, having low energy spin-half (spinon) or spin-1 excitations. Although spins are `disordered', they posses subtle topological orders and some times chiral orders. RVB states are easily appreciated and seem natural in the quantum fluctuation dominated 1D world. In 2 and 3D, competing orders such as antiferromagnetism, charge order or even superconductivity often hide an underlying robust quantum spin liquid state. Introduction of additional spin interactions or doping of delocalized charges, or finite temperatures, could frustrate the long range magnetic order and reveal a robust RVB state. To this extent they are natural in 2D and above. We present a brief history of insulating RVB states. Then we summarise our own recent theory of RVB states for 2 and 3D systems, including some newly synthesised ones: i) boron doped diamond, ii) \nxcob, iii) quasi 2D organic conductors and iv) a 2D graphene sheet.