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Tuning the Two-Electron Hybridization and Spin States in Parallel-Coupled InAs Quantum Dots
Malin Nilsson1, Florinda Viñas Boström1, Sebastian Lehmann1
1Division of Solid State Physics and NanoLund, Lund University, Box 118, S-221 00 Lund, Sweden.
Physical Review Letters
|October 27, 2018
Summary
We investigated spin transport in double quantum dots (DQDs) using InAs nanowires. The study reveals how interdot coupling strength affects spin-orbit-induced energy level transitions, crucial for quantum information processing.
Area of Science:
- Quantum Physics
- Condensed Matter Physics
- Nanotechnology
Background:
- Double quantum dots (DQDs) are essential for quantum computing.
- Understanding spin transport in DQDs is key to developing quantum technologies.
- InAs nanowires offer unique properties for fabricating advanced quantum devices.
Purpose of the Study:
- To investigate spin transport in one- and two-electron regimes of parallel-coupled DQDs.
- To explore the dependence of the spin-orbit-induced singlet-triplet anticrossing on interdot tunnel coupling (t).
- To characterize the impact of tunable coupling on spin dynamics in nanowire-based DQDs.
Main Methods:
- Fabrication of DQDs in InAs nanowires using crystal-phase engineering and electrostatic gating.
- Tunable interdot tunnel coupling (t) over one order of magnitude.
- Excited-state spectroscopy to measure B-field-induced singlet-to-triplet transitions and anticrossing magnitudes.
Main Results:
- Detailed studies of singlet-to-triplet ground state transitions as a function of interdot coupling (t).
- Quantified the magnitude of the spin-orbit-induced singlet-triplet anticrossing, finding values up to 230 µeV for strong coupling.
- Experimental findings were validated by rate equation calculations using a DQD model.
Conclusions:
- The interdot tunnel coupling significantly influences spin-orbit effects in DQDs.
- Precise control over coupling in InAs nanowire DQDs enables detailed studies of spin dynamics.
- The results provide valuable insights for the design and control of spin qubits.
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