Easy-axis ferromagnetic chain on a metallic surface

Abstract

The phases and excitation spectrum of an easy-axis ferromagnetic chain of S=1/2 magnetic impurities built on the top of a clean metallic surface are studied. As a function of the (Kondo) coupling to the metallic surface and at low temperatures, the spin chain exhibits a quantum phase transition from an Ising ferromagnetic phase with long-range order to a paramagnetic phase where quantum fluctuations destroy the magnetic order. In the paramagnetic phase, the system consists of a chain of Kondo-singlets where the impurities are completely screened by the metallic host. In the ferromagnetic phase, the excitations above the Ising gap are damped magnons, with a finite lifetime arising due to the coupling to the substrate. We discuss the experimental consequences of our results to spin-polarized electron energy loss spectroscopy (SPEELS), and we finally analyze possible extensions to spin chains with S>1/2.

21 pages, 5 figures

References in corpus (7)

• The numerical renormalization group method for quantum impurity systems
• Exchange interaction between single magnetic adatoms
• Phase diagram and critical exponents of a dissipative Ising spin chain in a transverse magnetic field
• Quantum criticality in a double quantum-dot system
• Dissipative Quantum Ising model in a cold atomic spin-boson mixture
• Quantum phase transition of Ising-coupled Kondo impurities
• Spin-exchange-induced dimerization of an atomic 1-D system