Related papers: Singlet-triplet relaxation in SiGe/Si/SiGe double …
In this theoretical study we qualitatively and quantitatively investigate the electric dipole spin resonance (EDSR) in a single Si/SiGe quantum dot in the presence of a magnetic field gradient, e.g., produced by a ferromagnet. We model a…
We calculate the longitudinal-acoustic phonon scattering rate for a vertical double quantum dot system with weak lateral confinement and show that a strong modulation of the single-electron excited states lifetime can be induced by an…
The spin relaxation of a two-dimensional electron system (2DES) formed in a symmetric quantum well is studied theoretically when the quantum well is parallel to the (110) plane of the zinc-blende structure, the spin polarization is…
We observe mixing between two-electron singlet and triplet states in a double quantum dot, caused by interactions with nuclear spins in the host semiconductor. This mixing is suppressed by applying a small magnetic field, or by increasing…
We have studied theoretically the possibility of ultra-fast manipulation of a single electron spin in 2D semiconductor quantum dots, by means of high-frequency time-dependent electric fields. The electron spin degree of freedom is excited…
Research on Si quantum dot spin qubits is motivated by the long spin coherence times measured in Si, yet the orbital spectrum of Si dots is increased as a result of the valley degree of freedom. The valley degeneracy may be lifted by the…
From our theoretical studies of resonant Raman transitions in two-electron quantum dots (artificial helium atoms) we show that in this system, the singlet-triplet Raman transitions are allowed (in polarized configuration) only in the…
We investigate the use of external time-dependent magnetic field for the control of the quantum states in a two-electron quantum ring. The hyperfine interaction of the confined electrons with surrounding nuclei couples the singlet state…
We propose a set of universal gate operations for the singlet-triplet qubit realized by two electron spins in a double quantum dot, in the presence of a fixed inhomogeneous magnetic field. All gate operations are achieved by switching the…
Electron states in a inhomogeneous Ge/Si quantum dot array with groups of closely spaced quantum dots were studied by conventional continuous wave ($cw$) ESR and spin-echo methods. We find that the existence of quantum dot groups allows to…
We develop the theory of single-electron silicon spin qubit relaxation in the presence of a magnetic field gradient. Such field gradients are routinely generated by on-chip micromagnets to allow for electrically controlled quantum gates on…
Quantum networks will rely on photons entangled to robust, local quantum registers for computation and error correction. We demonstrate control of and entanglement in a fully connected three-qubit $^{13}\mathrm{C}$ nuclear spin register in…
We calculate electron and nuclear spin relaxation rates in a quantum dot due to the combined action of Nyquist noise and electron-nuclei hyperfine or spin-orbit interactions. The relaxation rate is linear in the resistance of the gate…
We have studied spin-flip transitions between Zeeman sublevels in GaAs electron quantum dots. Several different mechanisms which originate from spin-orbit coupling are shown to be responsible for such processes. It is shown that…
We investigate a silicon single-electron transistor (SET) in a metal-oxide-semiconductor (MOS) structure by applying a magnetic field perpendicular to the sample surface. The quantum dot is defined electrostatically in a point contact…
We calculate that the electron states of strained self-assembled Ge/Si quantum dots provide a convenient two-state system for electrical control. An electronic state localized at the apex of the quantum dot is nearly degenerate with a state…
We implement silicon quantum dot devices with two layers of gate electrodes using a self-alignment technique, which allows for ultra-small gate lengths and intrinsically perfect layer-to-layer alignment. In a double quantum dot system, we…
We study the effect of an external magnetic field in the Kondo regime of a double-quantum-dot system in which a strongly correlated dot (the "hanging dot") is coupled to a second, noninteracting dot that also bridges the gap between two…
We study the electric-dipole transitions for a single electron in a double quantum dot located in a semiconductor nanowire. Enabled by spin-orbit coupling (SOC), electric-dipole spin resonance (EDSR) for such an electron can be generated…
Ground state of two-electron quantum dots in single-valley materials like GaAs is always a spin singlet regardless of what the potential and interactions are. This statement cannot be generalized to the multi-valley materials like $n$-doped…