2006/12/01 by K. Kikoin, Kikoin, K., Y. Avishai +1
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic properties of thin films #Magnetism in coordination complexes #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.cond-mat/0612028
36 pages, 10 figures. To be published as a Lecture Note of the Int. School on Physics of Low-D Nanoscopic Systems in Saha Institute of Nuclear Physics, Calcutta (Springer Verlag, Berlin)
arxiv created 2006/12/01 · openalex publication_date 2006/12/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recent advancement in fabrication technologies enable the construction of nano-objects with rather rich internal structures such as double or triple quantum dots, which can then be regarded as artificial molecules. The main new ingredient in the study of the Kondo effect in such artificial (and also in natural) molecules is the internal symmetry of the nano-object, which proves to play a crucial role in the construction of the effective exchange Hamiltonian. This internal symmetry combines continuous spin symmetry SU(2) and discrete point symmetry (such as mirror reflections for double dots or discrete C3v rotation for equilateral triangular dots. When these artificial molecules are attached to metallic leads, the set of dot operators appearing in the effective exchange Hamiltonian generate a group which is refereed to as the dynamical symmetry group of the system dot-leads [mostly SO(n) or SU(n)], and the pertinent group parameters (such as the value of n) can be controlled by experiment. In this short review we clarify and expand these concepts and discuss some specific examples. In particular we concentrate on the difference between the chain geometry and the ring geometry. When a perpendicular magnetic field is applied in the ring geometry, its gauge symmetry U(1) is involved in the interplay with the spin and orbital dynamics of the dot.