Functional renormalization group approach to the singlet–triplet transition in quantum dots

We present a functional renormalization group approach to the zero bias transport properties of a quantum dot with two different orbitals and in the presence of Hund's coupling. Tuning the energy separation of the orbital states, the quantum dot can be driven through a singlet–triplet transitio...

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Bibliographic Details
Main Authors: Shelykh, Ivan A., Hasselmann, N., Magnusson, E. B.
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2013
Subjects:
Online Access:https://hdl.handle.net/10356/99217
http://hdl.handle.net/10220/17204
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Institution: Nanyang Technological University
Language: English
Description
Summary:We present a functional renormalization group approach to the zero bias transport properties of a quantum dot with two different orbitals and in the presence of Hund's coupling. Tuning the energy separation of the orbital states, the quantum dot can be driven through a singlet–triplet transition. Our approach, based on the approach by Karrasch et al (2006 Phys. Rev. B 73 235337), which we apply to spin-dependent interactions, recovers the key characteristics of the quantum dot transport properties with very little numerical effort. We present results on the conductance in the vicinity of the transition and compare our results both with previous numerical renormalization group results and with predictions of the perturbative renormalization group.