# Single-component molecular material hosting antiferromagnetic and spin-gapped Mott subsystems

## TL;DR

This study reveals a unique single-molecular material, Cu(tmdt)$_{2}$, hosting both antiferromagnetic and spin-gapped Mott subsystems, identified through NMR measurements, showcasing a hybrid insulator with distinct magnetic properties.

## Contribution

The paper reports the discovery of a single-molecular system with coexisting antiferromagnetic and spin-gapped Mott subsystems, a novel hybrid magnetic state within a single molecule.

## Key findings

- Identification of a spin-gapped Mott subsystem via NMR
- Evidence of antiferromagnetic chains within the molecule
- Demonstration of a hybrid Mott insulator with distinct dimensionalities

## Abstract

We investigated a system based solely on a single molecular species, Cu(tmdt)$_{2}$, accommodating $d$ and ${\pi}$ orbitals within the molecule. $^{13}$C nuclear magnetic resonance measurements captured singlet-triplet excitations of ${\pi}$ spins indicating the existence of a ${\pi}$-electron-based spin-gapped Mott insulating subsystem, which has been hidden by the large magnetic susceptibility exhibited by the $d$ spins forming antiferromagnetic chains. The present results demonstrate a unique hybrid Mott insulator composed of antiferromagnetic and spin-singlet Mott subsystems with distinctive dimensionalities.