Negative spin exchange in a multielectron quantum dot

Abstract

By operating a one-electron quantum dot (fabricated between a multielectron dot and a one-electron reference dot) as a spectroscopic probe, we study the spin properties of a gate-controlled multielectron GaAs quantum dot at the transition between odd and even occupation number. We observe that the multielectron groundstate transitions from spin-1/2-like to singlet-like to triplet-like as we increase the detuning towards the next higher charge state. The sign reversal in the inferred exchange energy persists at zero magnetic field, and the exchange strength is tunable by gate voltages and in-plane magnetic fields. Complementing spin leakage spectroscopy data, the inspection of coherent multielectron spin exchange oscillations provides further evidence for the sign reversal and, inferentially, for the importance of non-trivial multielectron spin exchange correlations.

8 pages, including 4 main figures and 2 supplementary figurures

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Cited by in corpus (29)

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• Simultaneous Operations in a Two-Dimensional Array of Singlet-Triplet Qubits
• Crosstalk error correction through dynamical decoupling of single-qubit gates in capacitively coupled singlet-triplet semiconductor spin qubits
• Spin of a multielectron quantum dot and its interaction with a neighboring electron
• Negative exchange interactions in coupled few-electron quantum dots
• Pretty good quantum state transfer on isotropic and anisotropic Heisenberg spin chains with tailored site dependent exchange couplings
• Highly tunable quadruple quantum dot in a narrow bandgap semiconductor InAs nanowire
• Robust energy selective tunneling readout of singlet triplet qubits under large magnetic field gradient
• Interplay of exchange and superexchange in triple quantum dots
• Measurement of tunnel coupling in a Si double quantum dot based on charge sensing
• Extended Hubbard model describing small multi-dot arrays in bilayer graphene
• Understanding the propagation of excitations in quantum spin chains with different kind of interactions
• Extended orbital modeling of spin qubits in double quantum dots
• Wigner-molecularization-enabled dynamic nuclear field programming
• Symmetry-controlled singlet-triplet transition in a double-barrier quantum ring
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• Robust entangling gate for capacitively coupled few-electron singlet-triplet qubits
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• Singlet-triplet transition in double quantum dots in two-dimensional topological insulators
• Microscopic theory on magnetic-field-tuned sweet spot of exchange interactions in multielectron quantum-dot systems
• Sign-switching of superexchange mediated by few electrons under non-uniform magnetic field
• Investigation of bi-particle states in gate-array-controlled quantum-dot systems aided by machine learning techniques
• Theory on electron-phonon spin dehphasing in GaAs multi-electron double quantum dots
• Influence of Random Telegraph Noise on Quantum Bit Gate Operation
• Exact solution of a family of staggered Heisenberg chains with conclusive pretty good quantum state transfer
• Negative exchange interaction in Si quantum dot arrays via valley-phase induced ${\mathbb{Z}}_2$ gauge field
• Exploring Entanglement Spectrum and Phase Diagram in multi-electron Quantum Dot Chains