Chiral spin currents and spectroscopically accessible single merons in quantum dots

Abstract

We provide unambiguous theoretical evidence for the formation of correlation-induced isolated merons in rotationally-symmetric quantum dots. Our calculations rely on neither the lowest-Landau-level approximation, nor on the maximum-density-droplet approximation, nor on the existence of a spin-polarized state. For experimentally accessible system parameters, unbound merons condense in the ground state at magnetic fields as low as $B^{\ast }=0.2$ T and for as few as N = 3 confined fermions. The four-fold degenerate ground-state at $B^{\ast }$ corresponds to four orthogonal merons $|QC⟩$ characterized by their topological chirality $C$ and charge $Q$. This degeneracy is lifted by the Rashba and Dresselhaus spin-orbit interaction, which we include perturbatively, yielding spectroscopic accessibility to individual merons. We further derive a closed-form expression for the topological chirality in the form of a chiral spin current and use it to both characterize our states and predict the existence of other topological textures in other regions of phase space, for example, at N=5. Finally, we compare the spin textures of our numerically exact meron states to ansatz wave-functions of merons in quantum Hall droplets and find that the ansatz qualitatively describes the meron states.

4 pages, 5 figures; minor title change, typos fixed

References in corpus (4)

• Universal quantum control of two-electron spin quantum bits using dynamic nuclear polarization
• Gate-controlled spin-orbit interaction in a parabolic GaAs/AlGaAs quantum well
• Controlling Spin Qubits in Quantum Dots
• Chiral Spin Textures of Strongly Interacting Particles in Quantum Dots