Vendredi 29 novembre 2019 à 11h00, Roman Engel-Herbert (Department of Materials Science and Engineering, The Pennsylvania State University) donnera un séminaire sur "Cleaning up the mess : Transport behavior of a correlated metal in the ultraclean limit"
Abstract :
Maturing the thin film growth process to reduce the level of defects is a prerequisite to study the intrinsic properties of materials. While the growth of stoichiometric complex transition metal oxides, in which the cation ratio and the cation to anion ratio both has to be controlled, has been found difficult, new thin film methods have been innovated offering a different growth kinetics, which has resulted in a dramatic improvement of film quality that are even superior to their bulk single crystal counterparts. This is particularly interesting because it opens an avenue to study electron correlation effects that are intrinsic to early transition metal perovskite materials.
In this talk I will present electronic transport anomalies observed for the strongly correlated metal SrVO3 in the ultraclean limit. Films with a low defect concentration, reflected by a high residual resistivity ratio of about 200, show a magnetic field dependence of the Hall coefficient, which becomes more pronounced at low temperatures, while films with a higher defect concentration and low residual resistivity of about 10 show a temperature and field independent Hall coefficient. The record high carrier mobility of SrVO3 at low temperature allows to experimentally access electronic transport in the high magnetic field limit, revealing a significant deviation from the theoretical values predicted for the carrier concentration, which will be discussed in light of non-Fermi liquid behavior in ultraclean SrVO3.
Séminaire - Roman Engel-Herbert
