Electrical control of spins and giant g-factors in ring-like coupled quantum dots

Abstract

Emerging theoretical concepts for quantum technologies have driven a continuous search for structures where a quantum state, such as spin, can be manipulated efficiently. Central to many concepts is the ability to control a system by electric and magnetic fields, relying on strong spin-orbit interaction and a large g-factor. Here, we present a new mechanism for spin and orbital manipulation using small electric and magnetic fields. By hybridizing specific quantum dot states at two points inside InAs nanowires, nearly perfect quantum rings form. Large and highly anisotropic effective g-factors are observed, explained by a strong orbital contribution. Importantly, we find that the orbital and spin-orbital contributions can be efficiently quenched by simply detuning the individual quantum dot levels with an electric field. In this way, we demonstrate not only control of the effective g-factor from 80 to almost 0 for the same charge state, but also electrostatic change of the ground state spin.

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Cited by in corpus (8)

• Josephson current via spin and orbital states of a tunable double quantum dot
• Josephson junction π-0 transition induced by orbital hybridization in a double quantum dot
• Symmetry-controlled singlet-triplet transition in a double-barrier quantum ring
• Measurements of anisotropic g-factors for electrons in InSb nanowire quantum dots
• Richardson model with complex level structure and spin-orbit coupling for hybrid superconducting islands: stepwise suppression of pairing and magnetic pinning
• Selective tuning of spin-orbital Kondo contributions in parallel-coupled quantum dots
• Josephson and persistent currents in a quantum ring between topological superconductors
• Spin-photon coupling using circular double quantum dots