Speaker
Julien Levallois
(DPMC - University of Geneva)
Description
J. Levallois (1), F. Lévy-Bertrand (1,2), M.K. Tran (1), D. Stricker (1), J.A. Mydosh (3), Y.-K. Huang (4) and D. van der Marel (1)
1) Département de Physique de la Matière Condensée,
Université de Genève, CH-1211 Genève 4, Switzerland
2) Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9, France
3) Kamerlingh Onnes Laboratory, Leiden University, 2300RA Leiden, The Netherlands
4) Van der Waals-Zeeman Institute, University of Amsterdam, 1018XE Amsterdam, The Netherlands
We present far-infrared reflectivity measurements on URu2Si2 as a function of temperature along the a-axis and the c-axis of the tetragonal structure. Our results demonstrate that in addition to a pronounced anisotropy, a partial gap emerges at ∼ 30 K, well above the hidden order temperature T_HO and whose amplitude seems to be T-independent and not affected by the hidden order transition. As this suppression of spectral weight coincides with the development, at the same energy, of a maximum in the scattering rate, indicating optical interband transitions, we propose that this partial gap is a hybridization gap and that this change in the bandstructure below 30 K is a precursor of the hidden order state. However, since these changes have no noticeable impact on the entropy nor on the DC transport properties, we suggest that this is a crossover phenomenon rather than a thermodynamic phase transition.
Primary author
Julien Levallois
(DPMC - University of Geneva)
