Gapless chiral spin liquid from a parton mean-field theory on the kagome lattice

• Ano de defesa: 2020
• Autor(a) principal: Oliviero, Fabrizio Giovanni
• Orientador(a): Pereira, Rodrigo Gonçalves
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Rio Grande do Norte
• Programa de Pós-Graduação: PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA
• País: Brasil
• Palavras-chave em Português: Quantum spin liquids; Kagome lattice; Parton construction; Mean-field; Gapless chiral spin liquid
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/29974

Quantum spin liquids are among the most studied phases of matter which depart from the paradigm of symmetry breaking order and Fermi-liquid theory. In this work, we investigated a spin-1/2 Heisenberg model on the kagome lattice with exchange interaction Jd between spins connected by the diagonals of the hexagons and a staggered chiral interaction Jχ that couples the three spins in the triangles. Applying parton construction, we show that the model can exhibit a gapless chiral quantum spin liquid phase in the regime of dominant Jχ. The gapless phase is equivalent to the one found in other mean-field solutions based on Majorana fermions with symmetry protected line Fermi surfaces. Our goal is to study the changes in the spectrum of the spinons as a function of the ratio Jd/|Jχ| for two diferent cases of a speci c ansatz in the mean-field theory. We expect that in the regime of relevant Jd, a non-coplanar ordered magnetic state appears, the cuboc-2 state. The apparent phase transition is analyzed in terms of the mean-field orders parameters and the search for instabilities in the generalized susceptibility. This work provides a unique example of a phase transition between a chiral spin liquid and a non-trivial ordered magnetic state.