# Fermionic algebraic quantum spin liquid in an octa-kagome frustrated antiferromagnet

## TL;DR

This paper studies the ground state and finite-temperature properties of a spin-1/2 Heisenberg antiferromagnet on an octa-kagome lattice, revealing a fermionic algebraic quantum spin liquid phase at the isotropic point.

## Contribution

It demonstrates the existence of a fermionic algebraic quantum spin liquid in an octa-kagome antiferromagnet using tensor network methods, identifying a quantum phase transition and characterizing different phases.

## Key findings

- Identifies a quantum phase transition at J_d/J_t=0.6.
- Finds a gapless spin liquid with power-law correlations at the isotropic point.
- Shows linear specific heat and constant susceptibility at low temperature.

## Abstract

We investigate the ground state and finite-temperature properties of the spin-1/2 Heisenberg antiferromagnet on an infinite octa-kagome lattice by utilizing state-of-the-art tensor network-based numerical methods. It is shown that the ground state has a vanishing local magnetization and possesses a $1/2$-magnetization plateau with up-down-up-up spin configuration. A quantum phase transition at the critical coupling ratio $J_{d}/J_{t}=0.6$ is found. When $0<J_{d}/J_{t}<0.6$, the system is in a valence bond state, where an obvious zero-magnetization plateau is observed, implying a gapful spin excitation; when $J_{d}/J_{t}>0.6$, the system exhibits a gapless excitation, in which the dimer-dimer correlation is found decaying in a power law, while the spin-spin and chiral-chiral correlation functions decay exponentially. At the isotropic point ($J_{d}/J_{t}=1$), we unveil that at low temperature ($T$) the specific heat depends linearly on $T$, and the susceptibility tends to a constant for $T\rightarrow 0$, giving rise to a Wilson ratio around unity, implying that the system under interest is a fermionic algebraic quantum spin liquid.