title: Kitaev exchange and field-induced quantum spin-liquid states in honeycomb α-RuCl3.
abstract: Large anisotropic exchange in 5d and 4d oxides and halides open the door to new types of magnetic ground states and excitations, inconceivable a decade ago. A prominent case is the Kitaev spin liquid, host of remarkable properties such as protection of quantum information and the emergence of Majorana fermions. Here we discuss the promise for spin-liquid behavior in the 4d5honeycomb halide α-RuCl3. From advanced electronic-structure calculations, we find that the Kitaev interaction is ferromagnetic, as in 5d5iridium honeycomb oxides, and indeed defines the largest superexchange energy scale. A ferromagnetic Kitaev coupling is also supported by a detailed analysis of the field-dependent magnetization. Using exact diagonalization and density-matrix renormalization group techniques for extended Kitaev-Heisenberg spin Hamiltonians, we find indications for a transition from zigzag order to a gapped spin liquid when applying magnetic field. Our results offer a unified picture on recent magnetic and spectroscopic measurements on this material and open new perspectives on the prospect of realizing quantum spin liquids in d5halides and oxides in general.
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors.forename: Ravi
authors.initials: R
authors.lastname: Yadav
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors.forename: Nikolay A
authors.initials: NA
authors.lastname: Bogdanov
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors.forename: Vamshi M
authors.initials: VM
authors.lastname: Katukuri
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Department of Physics, Technical University Dresden, Helmholtzstrasse 10, 01069 Dresden, Germany.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nishimoto
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Department of Physics, Technical University Dresden, Helmholtzstrasse 10, 01069 Dresden, Germany.|Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van den Brink
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors.forename: Liviu
authors.initials: L
authors.lastname: Hozoi