Impact of the valley orbit coupling on exchange gate for spin qubits in silicon quantum dots
arXiv:2107.00732
Abstract
The presence of degenerate conduction band valleys and how they are mixed by interfaces play critical roles in determining electron interaction and spectrum in a silicon nanostructure. Here we investigate how the valley phases affect the exchange interaction in a symmetric two-electron silicon double quantum dot. Through a configuration interaction calculation, we find that exchange splitting is suppressed at a finite value of valley phase difference between the two dots, and reaches its minimum value ({\sim} 0) when the phase difference is π. Such a suppression can be explained using the Hubbard model, through the valley-phase-dependent dressing by the doubly occupied states on the ground singlet and triplet states. The contributions of the higher orbital states also play a vital role in determining the value of the exchange energy in general, which is a crucial parameter for applications such as exchange gates for spin qubits.
arXiv comment15 pages, 11 Figures
References in corpus (29)
- Quantum Computation with Quantum Dots
- Spins in few-electron quantum dots
- Coupled quantum dots as quantum gates
- Silicon Quantum Electronics
- Universal Quantum Computation with the Exchange Interaction
- Demonstration of Entanglement of Electrostatically Coupled Singlet-Triplet Qubits
- Hilbert space structure of a solid state quantum computer: two-electron states of a double quantum dot artificial molecule
- Spin-valley lifetimes in a silicon quantum dot with tunable valley splitting
- Noise suppression using symmetric exchange gates in spin qubits
- Valley Splitting Theory of SiGe/Si/SiGe Quantum Wells
- Theory of valley-orbit coupling in a Si/SiGe quantum dot
- Cancellation of Spin-Orbit Effects in Quantum Gates Based on the Exchange Coupling in Quantum Dots
- Physical mechanisms of interface-mediated intervalley coupling in Si
- Valley-based noise-resistant quantum computation using Si quantum dots
- Exchange coupling in silicon quantum dots: Theoretical considerations for quantum computation
- Optimized cavity-mediated dispersive two-qubit gates between spin qubits
- Spin-based quantum computation in multielectron quantum dots
- Quantum dot spin qubits in Silicon: Multivalley physics
- Spin relaxation in a Si quantum dot due to spin-valley mixing
- Dispersive readout of valley splittings in cavity-coupled silicon quantum dots
- Disorder-induced valley-orbit hybrid states in Si quantum dots
- Effects of Interface Steps on the Valley Orbit coupling in a Si/SiGe quantum dot
- Probing the Spatial Variation of the Inter-Valley Tunnel Coupling in a Silicon Triple Quantum Dot
- Impact of valley phase and splitting on readout of silicon spin qubits
- Valley Phase and Voltage Control of Coherent Manipulation in Si Quantum Dots
- Suppression of charge noise using barrier control of a singlet-triplet qubit
- Coulomb interaction and valley-orbit coupling in Si quantum dots
- Coherent electron transport in silicon quantum dots
- Electric-dipole-induced resonance and decoherence of a dressed spin in a quantum dot