2006/12/16 by A. I. Posazhennikova, Anna Posazhennikova, Babak Bayani +3
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Magnetic properties of thin films #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.75.245329
published as Phys. Rev. B 75, 245329 (2007). · 16 pages, 10 figures
arxiv created 2006/12/16 · openalex publication_date 2007/06/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We discuss the physics of a spin-1 quantum dot, coupled to two metallic leads, and develop a simple model for the temperature dependence of its conductance. Such quantum dots are described by a two-channel Kondo model with asymmetric coupling constants, and the spin screening of the dot by the leads is expected to proceed via a two-stage process. When the Kondo temperatures TK1 and TK2 of each channel are widely separated on cooling, the dot passes through a broad crossover regime TK2⪡T⪡TK1 dominated by underscreened Kondo physics. A singular or non-Fermi-liquid correction to the conductance develops in this regime. At the lowest temperatures, destructive interference between resonant scattering in both channels leads to the eventual suppression of the conductance of the dot. We develop a model to describe the growth, and ultimate suppression, of the conductance in the two channel Kondo model as it is screened successively by its two channels. Our model is based upon large-N approximation in which the localized spin degrees of freedom are described using the Schwinger boson formalism.