Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 53: Correlated Electrons: Heavy Fermions

TT 53.1: Vortrag

Donnerstag, 14. März 2013, 09:30–09:45, H19

Formation of the coherent heavy fermion liquid at the ‘hidden order’ transition in URu₂Si₂ — Shouvik Chatterjee¹, •Jan Trinckauf², Torben Hänke², Daniel E. Shai¹, John W. Harter¹, Travis J. Williams³, Graeme M. Luke³, Kyle M. Shen^1,4, and Jochen Geck² — ¹Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York 14853, USA — ²Leibniz Institute for Solid State and Materials Research IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany — ³Dept. of Physics and Astronomy, McMaster University, 1280 Main St. West, Hamilton, Ontario L8S 4M1, Canada — ⁴Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA

We present angle-resolved photoemission (ARPES) spectra of the heavy-fermion superconductor URu₂Si₂. Detailed measurements as a function of both excitation photon energy and temperature allow us to disentangle a variety of spectral features, revealing the evolution of the low energy electronic structure at the hidden order transition. We directly observe that precisely at THO, localized and fluctuating electronic states rapidly hybridize with light conduction states, forming a well-defined heavy band coincident with a dramatic reduction in the scattering rate. We thereby demonstrate that in URu₂Si₂, the formation of the coherent heavy fermion liquid occurs via a thermodynamic phase transition into the HO phase. This behavior is in stark contrast with the gradual crossover expected in Kondo lattice systems, suggesting the possibility of multiple pathways towards the creation of heavy fermionic states.