Banca de DEFESA: FABRIZIO GIOVANNI OLIVIERO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FABRIZIO GIOVANNI OLIVIERO
DATE: 17/06/2020
TIME: 14:00
LOCAL: Videoconferência
TITLE:

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

KEY WORDS:

Quantum spin liquids, kagome lattice, parton construction,
mean-field, gapless chiral spin liquid

PAGES: 80
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

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 different cases of a specific 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 generalized susceptibility.
This work provides a unique example of a phase transition between a chiral spin liquid and a non-trivial ordered magnetic
state.

BANKING MEMBERS:
Interno - 404927 - ALVARO FERRAZ FILHO
Externo à Instituição - ERIC DE CASTRO E ANDRADE - USP
Presidente - 1313663 - RODRIGO GONCALVES PEREIRA