Room-temperature Kondo effect in atom-surface scattering: Dynamical 1/N approach

Article

关键词: ANDERSON-IMPURITY MODEL;    DILUTE MAGNETIC-ALLOYS;    MANY-BODY THEORY;    CHARGE-TRANSFER;    RENORMALIZATION-GROUP;    ION NEUTRALIZATION;    AUGER;    SUSCEPTIBILITY;    EXCHANGE;    SHIFTS;   

DOI  :  10.1103/PhysRevB.58.6982

来源: SCIE

【 摘 要 】

The Kondo effect may be observable in some atom-surface scattering experiments, in particular, those involving alkaline-earth atoms. By combining Keldysh techniques with the noncrossing (NCA) approximation to solve the time-dependent Newns-Anderson Hamiltonian in the U-->infinity limit, Shao, Nordlander, and Langreth found an anomalously strong surface-temperature dependence of the outgoing charge state fractions. Here we employ a dynamical 1/N expansion with a finite Coulomb interaction U to give a more realistic description of the scattering process. We test the accuracy of the 1/N expansion in the N= 1 case of spinless fermions against the exact independent particle solution. We then compare results obtained in the U-->proportional to limit with the NCA at N=4 and recover qualitative features already found. Finally, we analyze the realistic situation of Ca atoms with U= 5.8 eV scattered off Cu(001) surfaces. Although the presence of the doubly ionized Ca2+ species can change the absolute scattered Ca+ yields, the temperature dependence is qualitatively the same as that found in the U-->infinity limit. One of the main difficulties that experimentalists face in attempting to detect this effect is that the atomic velocity must be kept small enough to limit kinematic smearing of the Fermi surface of the metal.

【 授权许可】

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