title: Chiral Spin-Orbital Liquids with Nodal Lines.
abstract: Strongly correlated materials with strong spin-orbit coupling hold promise for realizing topological phases with fractionalized excitations. Here, we propose a chiral spin-orbital liquid as a stable phase of a realistic model for heavy-element double perovskites. This spin liquid state has Majorana fermion excitations with a gapless spectrum characterized by nodal lines along the edges of the Brillouin zone. We show that the nodal lines are topological defects of a non-Abelian Berry connection and that the system exhibits dispersing surface states. We discuss some experimental signatures of this state and compare them with properties of the spin liquid candidate Ba_{2}YMoO_{6}.
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, C.P. 369, São Carlos, São Paulo 13560-970, Brazil.
authors.forename: W M H
authors.initials: WM
authors.lastname: Natori
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, C.P. 369, São Carlos, São Paulo 13560-970, Brazil.|Instituto de Física Teórica, Universidade Estadual Paulista, Rua Dr. Bento Teobaldo Ferraz, 271-Bloco II, 01140-070 São Paulo, São Paulo, Brazil.
authors.forename: E C
authors.initials: EC
authors.lastname: Andrade
authors.affiliation: Instituto de Física Gleb Wataghin, Unicamp, Rua Sérgio Buarque de Holanda, 777, CEP 13083-859 Campinas, São Paulo, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Miranda
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, C.P. 369, São Carlos, São Paulo 13560-970, Brazil.|International Institute of Physics, Universidade Federal do Rio Grande do Norte, 59078-970 Natal-RN, Brazil and Departamento de Física Teórica e Experimental Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN, Brazil.
authors.forename: R G
authors.initials: RG
authors.lastname: Pereira