About the talk
Landau’s Fermi liquid has proved extremely influential in the treatment of strongly correlated electrons in metals. Historically, the theory was inspired by another fermionic quantum liquid, namely the normal liquid 3He. Thermal conductivity of 3He conforms to this theory but, contrary to a common belief, only at very low temperatures. The deviation from the expected temperature dependence can be explained by assuming that in addition to Landau’s quasi-particles, there is another contribution to heat transport by a collective sound mode with a T1/2 temperature dependence. In the hydrodynamic limit, the celebrated zero sound cannot be distinguished from the first sound. The empirical expression for this second channel of heat transport is equivalent to a quantum version of the Bridgman equation for thermal conductivity of classical liquids. The presence of such collective mode in strongly correlated metallic Fermi liquids may explain the mystery of a downward deviation from the canonical quadratic behavior below the Fermi degeneracy temperature.
About the speaker
Kamran Behnia obtained his PhD in 1990 in Grenoble. The subject of his thesis was thermal transport in heavy-fermion superconductor UPt3. He then spent two years as a postdoctoral fellow at University of Geneva. In 1992, he was employed by Centre National de la Recherche Scientifique (CNRS) and spent seven years working on organic and cuprate superconductors at Paris-Sud University. Since 2000, he has been based at Ecole Supérieure de Physique et de Chimie Industrielles (ESPCI) in Paris. His research focuses on collective quantum phenomena in a variety of solids ranging from semimetals to superconductors. His book Fundamentals of Thermoelectricity was published by Oxford University Press in 2015. He became a fellow of American Physical Society in 2012. From 2013 to 2019 he was a Divisional Associate Editor (DAE) of Physical Review Letters and a member of the Board of Reviewing Editors (BoRE) of Science . In 2021, he was awarded the Jaffé prize by the French Academy of Sciences.