Related papers: Singlet-triplet relaxation in multivalley silicon …
We study single and double quantum dots defined electrostatically within silicene. The spin-valley structure of the confined single- and two-electron system is determined and the effects of the intervalley scattering induced by the crystal…
We report a successful measurement of the magnetic field-induced spin singlet-triplet transition in silicon-based coupled dot systems. Our specific experimental scheme incorporates a lateral gate-controlled Coulomb-blockaded structure in Si…
We discuss the rate of relaxation of the total spin in the two-electron droplet in the vicinity of the magnetic field driven singlet-triplet transition. The total spin relaxation is attributed to spin-orbit and electron-phonon interactions.…
Electron spins in silicon quantum dots are excellent qubits because they have long coherence times, high gate fidelities, and are compatible with advanced semiconductor manufacturing techniques. The valley degree of freedom, which results…
The presence of non-degenerate valley states in silicon can drastically affect electron dynamics in silicon-based heterostructures, leading to electron spin relaxation and spin-valley coupling. In the context of solid-state spin qubits, it…
The valley degree of freedom in the electronic band structure of silicon, graphene, and other materials is often considered to be an obstacle for quantum computing (QC) based on electron spins in quantum dots. Here we show that control over…
We estimate the spin relaxation rate due to spin-orbit coupling and acoustic phonon scattering in weakly-confined quantum dots with up to five interacting electrons. The Full Configuration Interaction approach is used to account for the…
Spin relaxation from a triplet excited state to a singlet ground state in a semiconductor quantum dot is studied by employing an electrical pump-and-probe method. Spin relaxation occurs via cotunneling when the tunneling rate is relatively…
We use numerically exact diagonalization to calculate the spin-orbit and phonon-induced triplet-singlet relaxation rate in a two-electron quantum dot exposed to a tilted magnetic field. Our scheme includes a three-dimensional description of…
We investigate the valley relaxation due to intervalley coupling in a single-electron bilayer graphene quantum dot. The valley relaxation is assisted by both the emission of acoustic phonons via the deformation potential and bond-length…
With silicon being the go-to material for spin qubits, and motivated by the demand of a scalable quantum computer architecture for fast and reliable quantum information transfer on-chip, we study coherent electron transport in a silicon…
The valley degree of freedom presents challenges and opportunities for silicon spin qubits. An important consideration for singlet-triplet states is the presence of two distinct triplets, comprised of valley vs. orbital excitations. Here we…
Spin-orbit coupling is relatively weak for electrons in bulk silicon, but enhanced interactions are reported in nanostructures such as the quantum dots used for spin qubits. These interactions have been attributed to various dissimilar…
We theoretically study the $(1,1)$ triplet to $(0,2)$ singlet relaxation rate in a lateral gate-defined double quantum dot tuned to the regime of Pauli spin blockade. We present a detailed derivation of the effective phonon density of…
We present the experimental observation of a large exchange coupling $J \approx 300$ $\mu$eV between two $^{31}$P electron spin qubits in silicon. The singlet and triplet states of the coupled spins are monitored in real time by a…
We develop a theory of effects of electron-electron collisions on the Dyakonov-Perel' spin relaxation in multi-valley quantum wells. It is shown that the electron-electron scattering rate which governs the spin relaxation is different from…
We investigate the spin relaxation induced by acoustic phonons in the presence of spin-orbit interactions in single electron Si/SiGe lateral coupled quantum dots. The relaxation rates are computed numerically in single and double quantum…
While bulk silicon has long been understood to exhibit relatively weak spin-orbit coupling (SOC), confinement of electrons to quantum dots (QDs) at a silicon heterointerface results in significantly larger SOC. This is a concern for…
In silicon spin qubits, the valley splitting must be tuned far away from the qubit Zeeman splitting to prevent fast qubit relaxation. In this work, we study in detail how the valley splitting depends on the electric and magnetic fields as…
We use temporally resolved intensity cross-correlation measurements to identify the biexciton-exciton radiative cascades in a negatively charged QD. The polarization sensitive correlation measurements show unambiguously that the excited two…