2007/04/30 by Takashi Hotta · 2 citations
Physics and Astronomy · #Advanced Chemical Physics Studies #Quantum and electron transport phenomena #Rare-earth and actinide compounds #cond-mat.str-el
paper · pdf · doi:10.1143/jpsj.76.084702
published as J. Phys. Soc. Jpn. 76, 084702 (2007). · 8 pages, 8 figures
arxiv created 2007/04/30 · openalex publication_date 2007/07/25 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We discuss Kondo behavior of a conduction electron system coupled with local optical phonon by analyzing the Anderson-Holstein model with the use of a numerical renormalization group (NRG) method. There appear three typical regions due to the balance between Coulomb interaction U\rm ee and phonon-mediated attraction U\rm ph. For U\rm ee>U\rm ph, we observe the standard Kondo effect concerning spin degree of freedom. Since the Coulomb interaction is effectively reduced as U\rm ee-U\rm ph, the Kondo temperature T\rm K is increased when U\rm ph is increased. On the other hand, for U\rm ee<U\rm ph, there occurs the Kondo effect concerning charge degree of freedom, since vacant and double occupied states play roles of pseudo-spins. Note that in this case, T\rm K is decreased with the increase of U\rm ph. Namely, T\rm K should be maximized for U\rm ee ≈ U\rm ph. Then, we analyze in detail the Kondo behavior at U\rm ee=U\rm ph, which is found to be explained by the polaron Anderson model with reduced hybridization of polaron and residual repulsive interaction among polarons. By comparing the NRG results of the polaron Anderson model with those of the original Anderson-Holstein model, we clarify the Kondo behavior in the competing region of U\rm ee ≈ U\rm ph.