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

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We investigate the quantum phase transition from antiferromagnetism (AF) to algebraic spin liquid (ASL). 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. 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 deconfined quantum criticalityLaughlindeconfinement,Senthildeconfinement,Kim1,Ichinosede 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.