Electromagnetic signatures of a chiral quantum spin liquid

• Published in: npj quantum materials Vol. 8; no. 1; pp. 63 - 8
• Main Authors: Banerjee, Saikat, Zhu, Wei, Lin, Shi-Zeng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 25.10.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/119/997; 639/766/119/2792; Condensed Matter Physics; Excitation; Magnetic properties and materials; Material Science; MATERIALS SCIENCE; Mean field theory; Partons; Physics; Physics and Astronomy; Quantum field theory; Quantum Physics; Quantum theory; Signatures; Spin liquid; Structural Materials; Surfaces and Interfaces; Thin Films; Topological matter
• ISSN: 2397-4648; 2397-4648
• DOI: 10.1038/s41535-023-00595-2

Quantum spin liquids (QSL) have emerged as a captivating subject within interacting spin systems that exhibit no magnetic ordering even at the lowest temperature accessible experimentally. However, definitive experimental evidence remains elusive. In light of the recent surge in theoretical and experimental interest in the half-filled Hubbard model on a triangular lattice, which offers the potential for stabilizing a chiral QSL, we investigate the electromagnetic signatures of this phase to facilitate experimental detection. Utilizing a combination of parton mean-field theory and unbiased density-matrix renormalization group calculations, we systematically examine the electrical charge and orbital electrical current associated with a spinon excitation in the chiral QSL. Additionally, we calculate the longitudinal and transverse optical conductivities below the Mott gap. Furthermore, employing quantum field theory analysis, we unravel the connection between spinon excitations and emergent as well as physical gauge fields. Our results demonstrate that the chiral QSL phase exhibits a distinct electromagnetic response, even within a Mott insulator regime. This finding holds great potential for enabling the experimental detection of this long-sought-after phase.