Monopole excitations in the $U(1)$ Dirac spin liquid on the triangular lattice

Fuente: arXiv
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Main Authors: Budaraju, Sasank, Parola, Alberto, Iqbal, Yasir, Becca, Federico, Poilblanc, Didier
Format: Preprint
Published: 2024
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author Budaraju, Sasank
Parola, Alberto
Iqbal, Yasir
Becca, Federico
Poilblanc, Didier
author_facet Budaraju, Sasank
Parola, Alberto
Iqbal, Yasir
Becca, Federico
Poilblanc, Didier
contents The $U(1)$ Dirac spin liquid might realize an exotic phase of matter whose low-energy properties are described by quantum electrodynamics in $2+1$ dimensions, where gapless modes exists but spinons and gauge fields are strongly coupled. Its existence has been proposed in frustrated Heisenberg models in presence of frustrating super-exchange interactions, by the (Abrikosov) fermionic representation of the spin operators [X.-G. Wen, \href{https://doi.org/10.1103/PhysRevB.65.165113}{Phys. Rev. B {\bf 65}, 165113 (2002)}], supplemented by the Gutzwiller projection. Here, we construct charge-$Q$ monopole excitations in the Heisenberg model on the triangular lattice with nearest- ($J_1$) and next-neighbor ($J_2$) couplings. In the highly frustrated regime, singlet and triplet monopoles with $Q=1$ become gapless in the thermodynamic limit; in addition, the energies for generic $Q$ agree with field-theoretical predictions, obtained for a large number of gapless fermion modes. Finally, we consider localized gauge excitations, in which magnetic $π$-fluxes are concentrated in the triangular plaquettes (in analogy with $\mathbb{Z}_2$ visons), showing that these kind of states do not play a relevant role at low energies. All our findings lend support to a stable $U(1)$ Dirac spin liquid in the $J_1-J_2$ Heisenberg model on the triangular lattice.
format Preprint
id arxiv_https___arxiv_org_abs_2410_18747
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Monopole excitations in the $U(1)$ Dirac spin liquid on the triangular lattice
Budaraju, Sasank
Parola, Alberto
Iqbal, Yasir
Becca, Federico
Poilblanc, Didier
Strongly Correlated Electrons
The $U(1)$ Dirac spin liquid might realize an exotic phase of matter whose low-energy properties are described by quantum electrodynamics in $2+1$ dimensions, where gapless modes exists but spinons and gauge fields are strongly coupled. Its existence has been proposed in frustrated Heisenberg models in presence of frustrating super-exchange interactions, by the (Abrikosov) fermionic representation of the spin operators [X.-G. Wen, \href{https://doi.org/10.1103/PhysRevB.65.165113}{Phys. Rev. B {\bf 65}, 165113 (2002)}], supplemented by the Gutzwiller projection. Here, we construct charge-$Q$ monopole excitations in the Heisenberg model on the triangular lattice with nearest- ($J_1$) and next-neighbor ($J_2$) couplings. In the highly frustrated regime, singlet and triplet monopoles with $Q=1$ become gapless in the thermodynamic limit; in addition, the energies for generic $Q$ agree with field-theoretical predictions, obtained for a large number of gapless fermion modes. Finally, we consider localized gauge excitations, in which magnetic $π$-fluxes are concentrated in the triangular plaquettes (in analogy with $\mathbb{Z}_2$ visons), showing that these kind of states do not play a relevant role at low energies. All our findings lend support to a stable $U(1)$ Dirac spin liquid in the $J_1-J_2$ Heisenberg model on the triangular lattice.
title Monopole excitations in the $U(1)$ Dirac spin liquid on the triangular lattice
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2410.18747