SU(2)-SU(4) Kondo Crossover and Emergent Electric Polarization in a Triangular Triple Quantum Dot

Abstract

We study an orbitally degenerate Kondo effect in a triangular triple quantum dot (TTQD), where the three dots are connected vertically with a single metallic lead through electron tunneling. Both spin and orbital degrees of freedom play an important role in the SU(4) Kondo effect. This is demonstrated by an equilateral TTQD Kondo system at half-filling, by Wilson's numerical renormalization group method. We show how an emergent electric polarization of the TTQD is associated with a crossover from SU(4) to SU(2) symmetry in the low-temperature state. A marked sign reversal of the electric polarization is generated by the fine-tuning of Kondo coupling with degenerate orbitals, which can be utilized to reveal orbital dynamics in the SU(4) Kondo effect.

5 pages, 5 figures

References in corpus (15)

• The numerical renormalization group method for quantum impurity systems
• Mechanical Control of Spin States in Spin-1 Molecules and the Underscreened Kondo Effect
• Quantum transport in carbon nanotubes
• Orbital Kondo effect in carbon nanotubes
• Observation of the two-channel Kondo effect
• Quantum phase transition in a single-molecule quantum dot
• Electronic Orbital Currents and Polarization in Mott Insulators
• Universal Scaling in Non-equilibrium Transport Through a Single-Channel Kondo Dot
• Magnetically Tunable Kondo - Aharonov-Bohm Effect in a Triangular Quantum Dot
• Charge frustration in a triangular triple quantum dot
• Numerical renormalization group study of two-channel three-impurity triangular clusters
• Transmission Phase in the Kondo Regime Revealed in a Two-Path Interferometer
• Topological spin liquid phase in a low-dimensional organic molecular compound
• Emergent Electric Polarization by Kondo Effect in a Triangular Triple Quantum Dot
• Ground-state properties of a triangular triple quantum dot connected to superconducting leads

Cited by in corpus (4)

• Spin-isospin Kondo effects for ${\Sigma }_c$ and ${\Sigma }_c^{\ast }$ baryons and $\bar{D}$ and ${\bar{D}}^{\ast }$ mesons
• Magnetic Kondo regimes in a frustrated half-filled trimer
• Antisymmetric Spin-Orbit Coupling Effect on Kondo-Induced Electric Polarization in a Triangular Triple Quantum Dot
• Kondo Screening of Local Moments in a Triangular Triple Quantum Dot Connected to Normal and Superconducting Leads