High-pressure structural anomalies and electronic transitions in the topological Kondo insulator SmB6
1 ID27 Beamline, European Synchrotron Radiation Facility - 71 Avenue des Martyrs, 38043 Grenoble, France
2 Center for Materials Crystallography (CMC), Department of Chemistry and iNANO, Aarhus University Langelandsgade 140, 8000 Aarhus C, Denmark
Received: 30 March 2015
Accepted: 11 June 2015
We have scrupulously investigated the high-pressure structural behaviour of the topological Kondo insulator SmB6 through synchrotron powder x-ray diffraction. Lattice modifications are observed at a critical pressure of for three separate compression experiments at ambient and low temperatures. The initially subtle compression of the Sm-B bond length shows a sharp kink downward at the critical pressure. These anomalies coincide with the phase diagram boundaries for the pressure-induced metallization and the concurrent appearance of long-range magnetic ordering in the compound. We propose a scenario of delocalization of 4f electrons and the gradual filling of 5d conduction bands, which can also provide some clarification on the valence dependence of Sm with pressure.
PACS: 61.50.Ks – Crystallographic aspects of phase transformations; pressure effects / 71.27.+a – Strongly correlated electron systems; heavy fermions / 71.30.+h – Metal-insulator transitions and other electronic transitions
© EPLA, 2015