Impurity effects on electronic structure, correlations, and entropy in elongated silicon quantum dots

Elongated quantum dots (EQDs) are promising candidates for scaling spin-qubit quantum computers by coupling qubits on semiconductor chips. However, these chips typically host structural and point charge impurities. The effects of impurities on the spectral properties, charge density, spin correlations, and entropy distribution in EQDs are characterized using valley augmented unrestricted Hartree-Fock and subsequent spin-and-space symmetry restoration. Wigner-molecular chains with zigzag geometric structures [1] and rich spin landscapes are shown to form within EQDs. The introduction of impurities induces the breaking of spatial symmetries and influences spin correlations. The dependence of the wavefunction’s spin and spatial structure on the strength and location of impurities is analyzed, and the intentional placement of impurities as a tunable mechanism for manipulating the wavefunction within an EQD is proposed.

Contributions by Dr. C. Yannouleas at the early stages of the program are acknowledged.

[1] A. Goldberg, C. Yannouleas, U. Landman, Phys. Rev. Applied 21, 064063 (2024).