Kondo Effect in Single Quantum Dot Systems : Study with Numerical Renormalization Group Method

概要

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The tunneling conductance is calctrlated as a fttnction of the gate voltage in wide tetnperattrrerange for the single quanttrrn dot systems xvith Couloutab interaction. We asstrme that twoorbitals are active f'or the t,tunneling process. We show that the Kondo tetnperature for eachorbital channel can be largel3' different. The ttrnneling through the Kondo resonance alnaostfully develops in the region T< 0.lT? x O.2T?, where T; is the [oxvest Kondo tenaperaturewhen the gate voltage is varied- At high teraaperattrres the conductance changes to the usualCotrlonab oscillations type. In the interraaediate temperattrre region, the degree of the coherencyof each orbital channel is different, so strange behaviors of the conductance can appear. Forexample, the conductance once increases and then decreases with tenuperature decreasing whenit is strppressed at T : 0 by the interf'erence cancellation between different channels. Theinteraction effects in the quantturn dot systems lead the sensitivities of' the condtrctance to theteraaperattzre and to the gate voltage.
社団法人日本物理学会の論文
1998-07-15