Tunneling through a quantum dot in local spin singlet-triplet crossover region with Kondo effect.
Tunneling conductance through a quantum dot is calculated around the local spin singlet-triplet crossover region including the Kondo effect. The calculation is carried out using the numerical renormalization group method. When the potential on the dot deepens, two electrons filling a lower energy orbital redistribute to gain Hund's coupling energy. This redistribution induces a bump in the conductance between the Coulomb peaks. The Kondo temperature on the bump is high due to the fluctuation on the singlet-triplet crossover region. The behaviors agree well with recent experiment.
Izumida
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Mesoscopic Correlation Project, ERATO, JST, NTT Atsugi R & D Center, Atsugi-shi, Kanagawa 243-0198, Japan.
Sakai
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Tarucha
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