Speaker: Meigan Aronson, UBC

Time: 10:00-11:00am

Location: BRIM 311

Abstract: Strong correlations between conduction electrons and magnetic moments reflect the competition between moment instabilities and magnetic order. Investigations of the resulting collective phases and complex phase diagrams in 3D compounds continue to reveal new behaviors, although similar efforts on 1D systems remain very limited due to a lack of suitable materials. We present here experimental evidence for 1D excitations in Ti4MnBi2, a moderately correlated metal consisting of well-separated chains of spin S = 1/2 moments. Inelastic neutron scattering (INS) measurements complemented by DMRG calculations show that Ti4MnBi2 is well described by the frustrated J1- J2 XXZ Hamiltonian, displaying a continuum of spinon excitations based on an underlying AF ↑↑↓↓ modulation of the Ising-like Mn moments along the chain. This is evidence for the one- dimensionality of the Mn subsystem. Fermi liquid behavior is observed in both the specific heat and electrical resistivity at low temperatures, indicating that the conduction electrons are three-dimensional, with magnetic correlations similar in strength to those found in metallic cuprates and ruthenates.