Magnetically Tunable Kondo–Aharonov-Bohm Effect in a Triangular Quantum Dot

The role of discrete orbital symmetry in mesoscopic physics is manifested in a system consisting of three identical quantum dots forming an equilateral triangle. Under a perpendicular magnetic field, this system demonstrates a unique combination of Kondo and Aharonov-Bohm features due to an interplay between continuous [spin-rotation $SU(2)$] and discrete (permutation $C_{3v}$) symmetries, as well as $U(1)$ gauge invariance. The conductance as a function of magnetic flux displays sharp enhancement or complete suppression depending on contact setups.

Figure 1

Triangular triple quantum dot in three-terminal (a) and two-terminal (b) configurations.

Figure 2

Upper panel: Evolution of the energy levels $E_A$ (solid line) and $E_{\pm }$ (dashed and dash-dotted line, respectively). Lower panel: Corresponding evolution of conductance ($G_0=\pi e^2/\hslash$).

Figure 3

Conductance as a function of magnetic field for ${\Phi }_2=0$ (left panel) and ${\Phi }_1={\Phi }_2=\Phi /2$ (right panel).