Dresden 2020 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 59: Correlated Electrons: Quantum Impurities and Kondo Physics; Other Materials

TT 59.6: Talk

Thursday, March 19, 2020, 16:15–16:30, HSZ 03

Theory of scanning tunnelling spectroscopy of Co adatoms in a magnetic field: A Kondo problem of an extended impurity — •Bimla Danu¹, Fakher F. Assaad¹, and Frédéric Mila² — ¹Institut fur Theoretische Physik und Astrophysik, Universitat Wurzburg, Am Hubland, D-97074 Wurzburg, Germany — ²Institute of Physics, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

The ability to build and manipulate various Kondo nano-structures has been demonstrated in many recent experiments using scanning tunneling spectroscopy (STS). For example, recent STS experiments on chains of Co adatoms have revealed a series of level crossings as a function of magnetic field. Motivated by these experimental studies, we explore the magnetic field induced Kondo effect that takes place at symmetry protected level crossings in finite Co adatom chains. In particular, we provide a quantitative theory of STS signal based on auxiliary-field quantum Monte Carlo simulations, and, show that the physics at the vicinity of level crossings is a Kondo problem of an extended Impurity.