Towards spin state tailoring of charged excitons in InGaAs quantum dots using oblique magnetic fields

Barr, K. and Hourahine, B. and Schneider, C. and Höfling, S. and Lagoudakis, K. G. (2024) Towards spin state tailoring of charged excitons in InGaAs quantum dots using oblique magnetic fields. Physical Review B: Condensed Matter and Materials Physics, 109 (7). 075433. ISSN 1098-0121 (https://doi.org/10.1103/PhysRevB.109.075433)

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Abstract

We investigate the effect of oblique magnetic field configurations on a singly charged self-assembled quantum dot system as a means to tune the spin composition of the ground electron spin eigenstates. Using magneto-optical spectroscopy and Stokes polarimetry techniques, we evaluate the anisotropic g factors and characterize the polarization properties of the charged quantum dot system under oblique fields. We compare the results to a simple model that captures the resulting level structure and polarization selection rules for arbitrary magnetic field orientations. Under oblique magnetic fields, the system's ground spin eigenstates are composed of unequal superpositions of the electron spins. This provides an additional degree of freedom to tailor the composition of the ground spin states in charged quantum dots and based on this we demonstrate spin pumping and initialization of the tailored ground states, confirming that the double-Λ level structure of the charged quantum dot persists in oblique magnetic fields. These combined results show that the uneven weightings of the tailored spin states can yield systems with interesting behaviors, with a potential towards developing spin-selective readout schemes to further enhance the capabilities of spin qubits.

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