Regensburg 2022 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Kondo Physics, f-Electron Systems and Heavy Fermions

TT 6.3: Vortrag

Montag, 5. September 2022, 15:30–15:45, H22

Spin chain on a metallic surface: Dissipation-induced order vs. Kondo entanglement — •Bimla Danu¹, Matthias Vojta², Tarun Grover³, and Fakher F. Assaad¹ — ¹Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany — ²Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany — ³Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA

We study the physics of an antiferromagnetic spin-1/2 chain Kondo coupled to a two dimensional metal as realized, for example, by depositing an array of magnetic adatoms on a metallic surface with scanning tunneling microscopy (STM) methods. Based on a field theoretical perturbative approach we show that at weak Kondo coupling this system maps onto a spin-1/2 chain coupled to a dissipative Ohmic bath. We argue that in this limit the dissipation induces long-range antiferromagnetic order along the spin chain. Using auxiliary field quantum Monte-Carlo simulations we show that the spin chain as a function of the Kondo coupling exhibits a quantum phase transition from an antiferromagnetic phase to a paramagnetic heavy fermi liquid phase. Since the heavy quasiparticle is not destroyed in the magnetic phase and at the critical point, this quantum phase transition falls in a Hertz-Millis-Moriya type quantum criticality. We discuss the relevance of our results in the context of STM experiments of magnetic adatom chains on metallic surfaces.