Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 71: Correlated Electrons: Poster Session

TT 71.2: Poster

Wednesday, March 18, 2015, 15:00–18:00, Poster B

Hidden order symmetry and superconductivity in Heavy Fermions investigated by quasiparticle interference — •Alireza Akbari^1,2 and Peter Thalmeier³ — ¹Asia Pacific Center for Theoretical Physics, POSTECH, Pohang, Gyeongbuk 790-784, Korea — ²MPI for Solid State Research, Stuttgart, Germany — ³MPI for the Chemical Physics of Solids, Dresden, Germany

The hidden order (HO) in URu₂Si₂ has been determined as a high rank multipole formed by itinerant 5f-electrons with distinct orbital structure imposed by the crystalline electric field. Because this can lead to a considerable number of different multipoles it is of great importance to use microscopic techniques that are sensitive to their subtle physical differences. Here we investigate whether quasiparticle interference (QPI) method can distinguish between the two most frequently proposed HO parameter models: the even rank-4 hexadecapole and the odd-rank-5 dotriacontapole model. We obtain the quasiparticle dispersion and reconstructed Fermi surface in each HO phase adapting an effective two-orbital model of 5f bands that reproduces the main Fermi surface sheets of the para phase. We show that the resulting QPI spectrum reflects directly the effect of fourfold symmetry breaking in the rank-5 model which is absent in the rank-4 model. Therefore we suggest that QPI method should give a possibility of direct discrimination between the two most investigated models of HO in URu₂Si₂. Furthermore the signature of proposed chiral d-wave superconducting (SC) order parameter in QPI of the coexisting HO+SC phase is investigated.