Two-body Wigner molecularization in asymmetric quantum dot spin qubits

Abstract

Coulomb interactions strongly influence the spectrum and the wave functions of few electrons or holes confined in a quantum dot. In particular, when the confinement potential is not too strong, the Coulomb repulsion triggers the formation of a correlated state, the Wigner molecule, where the particles tend to split apart. We show that the anisotropy of the confinement potential strongly enhances the molecularization process and affects the performances of quantum-dot systems used as spin qubits. Relying on analytical and numerical solutions of the two-particle problem -- both in a simplified single-band approximation and in realistic setups -- we highlight the exponential suppression of the singlet-triplet gap with increasing anisotropy. We compare the molecularization effects in different semiconductor materials and discuss how they specifically hamper Pauli spin blockade readout and reduce the exchange interactions in two-qubit gates.

12 pages and 8 figures in the main text + 5 pages of appendices

References in corpus (7)

• Squeezed hole spin qubits in Ge quantum dots with ultrafast gates at low power
• A molecular state of correlated electrons in a quantum dot
• Simple model for electrical hole spin manipulation in semiconductor quantum dots: Impact of dot material and orientation
• Correlated electrons in optically-tunable quantum dots: Building an electron dimer molecule
• Signatures of Wigner Localization in Epitaxially Grown Nanowires
• Interacting holes in Si and Ge double quantum dots: from a multiband approach to an effective-spin picture
• Impact of the valley orbit coupling on exchange gate for spin qubits in silicon quantum dots

Cited by in corpus (17)

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• Quantum Wigner molecules in moiré materials
• Wigner molecules and hybrid qubits
• High-precision real-space simulation of electrostatically-confined few-electron states
• Non-reciprocal Pauli Spin Blockade in a Silicon Double Quantum Dot
• Wigner molecules in phosphorene quantum dots
• Valleytronic full configuration-interaction approach: An application to the excitation spectra of Si double-dot qubits
• Wigner-molecule supercrystal in transition-metal dichalcogenide moiré superlattices: Lessons from the bottom-up approach
• Wigner-molecularization-enabled dynamic nuclear field programming
• Crystal-field effects in the formation of Wigner-molecule supercrystals in moiré TMD superlattices
• True decoherence-free-subspace derived from a semiconductor double quantum dot Heisenberg spin-trimer
• Variability of hole spin qubits in planar Germanium
• Dressed basis sets for the modeling of exchange interactions in double quantum dots
• Anomalous zero-field splitting for hole spin qubits in Si and Ge quantum dots