# Fragmented Electronic Spins with Quantum Fluctuations in Organic Mott Insulators near Quantum Spin Liquid

## TL;DR

This study uses 13C NMR to reveal unconventional fragmentation of electronic spins in organic Mott insulators near quantum spin liquids, highlighting intramolecular correlations and quantum fluctuations.

## Contribution

It demonstrates the presence of fragmented electronic spins with quantum fluctuations in organic Mott insulators, challenging single band models and emphasizing intramolecular electronic correlations.

## Key findings

- Detection of two distinct magnetic moments within molecules
- Unconventional spin fragmentation due to nearly degenerate orbitals
- Evidence of quantum fluctuations and fractionalized excitations

## Abstract

Magnetic structures of organic Mott insulators X[Pd(dmit)2]2 (X=Me4P, Me4Sb), of which electronic states are located near quantum spin liquid (X=EtMe3Sb), are demonstrated by 13C NMR. Antiferromagnetic spectra and nuclear relaxations show two distinct magnetic moments within each Pd(dmit)2 molecule, which cannot be described by single band dimer-Mott model and requires intramolecular electronic correlation. This unconventional fragmentation of S = 1/2 electron spin with strong quantum fluctuation is presumably caused by nearly degenerated intramolecular multiple orbitals, and shares a notion of quantum liquids where electronic excitations are fractionalized and S = 1/2 spin is no longer an elementary particle.