# Altermagnetic Shastry-Sutherland fullerene networks

## TL;DR

This paper introduces altermagnetic Shastry-Sutherland fullerene networks, a new class of molecular quantum materials exhibiting diverse quantum phases and unique magnetic properties, accessible through strain tuning.

## Contribution

It presents the design and analysis of a novel molecular network with altermagnetic order, expanding the landscape of quantum magnetic materials with potential for scalable applications.

## Key findings

- Discovery of an altermagnetic ground state with compensated spins.
- Identification of a rich phase diagram including quantum spin liquid and dimer phases.
- Demonstration of strain-tunable quantum phases in molecular networks.

## Abstract

The interplay between quantum magnetism and many-body physics is of fundamental importance in condensed matter physics. %Magnetic exchange interactions in frustrated lattices give rise to rich phase diagrams. Molecular building blocks provide a versatile platform for exploring the exotic quantum phases arising from complex orderings in frustrated lattices. Here we demonstrate a showcase system based on altermagnetic Shastry-Sutherland fullerene networks, which can be constructed from a C$_{40}$ molecular synthon with two effective spin-1/2 sites due to the resonance structures. The charge-neutral, pure-carbon systems exhibit an altermagnetic ground state with fully compensated spins arranged in alternating C$_{40}$ units in a 2D rutile-like lattice, leading to $d$-wave splitting of the spin-polarised electronic band structure and strong chiral-split magnons. We report a rich phase diagram including altermagentic, quantum spin liquid, plaquette, and dimer phases, which can be accessed via moderate strains. Our findings open a new avenue for exploring quantum many-body physics based on scalable, chemically-feasible, molecular quantum materials.