Deconfined Quantum Criticality at the Quantum Phase Transition from Antiferromagnetism to Algebraic Spin Liquid

TL;DR

This paper explores a novel quantum critical point between antiferromagnetism and algebraic spin liquid, proposing fractionalization of spinons and their confinement-deconfinement dynamics, advancing understanding of deconfined quantum criticality.

Contribution

It introduces a new fractionalization mechanism involving spin 1/2 bosonic and spinless fermionic spinons at the quantum critical point, linking deconfined criticality with phase transitions.

Findings

Spin 1/2 fermionic spinons fractionalize into bosonic spinons and spinless fermions at the QCP.

Condensation of bosonic spinons leads to antiferromagnetism with confined spinons.

Deconfined fermionic spinons describe the algebraic spin liquid phase.

Abstract

We investigate the quantum phase transition from antiferromagnetism ($AF$) to algebraic spin liquid ($ASL$). {\it We propose that spin 1/2 fermionic spinons in the $ASL$ fractionalize into spin 1/2 bosonic spinons and spinless fermions at the quantum critical point ($QCP$) between the $AF$ and the $ASL$}. Condensation of the bosonic spinons leads to the $AF$, where the condensed bosonic spinons are confined with the spinless fermions to form the fermionic spinons. These fermionic spinons are also confined to make antiferromagnons as elementary excitations in the $AF$. {\it Approaching the $QCP$ from the $AF$, spin 1 critical antiferromagnetic fluctuations are expected to break up into spin 1/2 critical bosonic spinons. Then, these bosonic spinons hybridize with spin 1/2 fermionic spinons, making spinless fermions}. As a result the fermionic spinons decay into the bosonic spinons and the spinless fermions. But, the spinless fermions are confined and thus, only the bosonic spinons emerge at the $QCP$. This coincides with the recent studies of {\it deconfined quantum criticality}\cite{Laughlin_deconfinement,Senthil_deconfinement,Kim1,Ichinose_de confinement}. When the bosonic spinons are gapped, the $ASL$ is realized. The bosonic spinons are confined with the spinless fermions to form the fermionic spinons. These fermionic spinons are deconfined to describe the $ASL$.