Logarithmic Fermi-Liquid Breakdown in NbFe2

M. Brando (1) , W. J. Duncan (1) , D. Moroni-Klementowicz (1) , C. Albrecht (1) , D. Grüner (2) , Rafik Ballou (3) , F. M. Grosche (1)

1 Department of Physics [Egham]
2 CPfS - Max Planck Institute for Chemical Physics of Solids
3 NEEL - MagSup - Magnétisme et Supraconductivité

The d-electron low temperature magnet NbFe2 is poised near the threshold of magnetism at ambient pressure, and can be tuned across the associated quantum critical point by adjusting the precise stoichiometry within the Nb1 yFe2 y homogeneity range. In a nearly critical single crystal (y = - 0.01), we observe a T$^{3/2} power-law dependence of the resistivity on temperature T and a logarithmic temperature dependence of the Sommerfeld coefficient $\gamma = C/T$ of the specific heat capacity C over nearly 2 orders of magnitude in temperature, extending down to 0.1 K.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

M. Brando, W. J. Duncan, D. Moroni-Klementowicz, C. Albrecht, D. Grüner, et al.. Logarithmic Fermi-Liquid Breakdown in NbFe2. Physical Review Letters, 2008, 101, pp.026401. ⟨10.1103/PhysRevLett.101.026401⟩. ⟨hal-00963916⟩