Related papers: Orbital and valley state spectra of a few-electron…
We report the demonstration of a low-disorder silicon metal-oxide-semiconductor (Si MOS) quantum dot containing a tunable number of electrons from zero to N=27. The observed evolution of addition energies with parallel magnetic field…
The valley-orbit coupling in a few-electron Si quantum dot is expected to be a function of its occupation number N. We study the spectrum of multivalley Si quantum dots for 2 <= N <= 4, showing that, counterintuitively, electron-electron…
Silicon quantum dot qubits must contend with low-lying valley excited states which are sensitive functions of the quantum well heterostructure and disorder; quantifying and maximizing the energies of these states are critical to improving…
The energies of valley-orbit states in silicon quantum dots are determined by an as yet poorly understood interplay between interface roughness, orbital confinement, and electron interactions. Here, we report measurements of one- and…
The energy spectrum and wave functions of electrons in a single silicon quantum dot provide valuable insights into the capabilities and limitations of such a system in quantum information processing. Here we investigate the low-lying…
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…
We study the few-electron eigenspectrum of a nanotube quantum dot with spin-orbit coupling. The two-electron phase diagram as a function of the length of the dot and the applied parallel magnetic field shows clear signatures of both…
The spin states of electrons confined in semiconductor quantum dots form a promising platform for quantum computation. Recent studies of silicon CMOS qubits have shown coherent manipulation of electron spin states with extremely high…
Spin-orbit effects, inherent to electrons confined in quantum dots at a silicon heterointerface, provide a means to control electron spin qubits without the added complexity of on-chip, nanofabricated micromagnets or nearby coplanar…
Electron states are studied for quantum dots in a strained Si quantum well, taking into account both valley and orbital physics. Realistic geometries are considered, including circular and elliptical dot shapes, parallel and perpendicular…
Electronic states in silicon quantum dots are examined theoretically, taking into account a multivalley structure of the conduction band. We find that (i) exchange interaction hardly works between electrons in different valleys. In…
We expand on previous work that treats relaxation physics of low-lying excited states in ideal, single electron, silicon quantum dots in the context of quantum computing. These states are of three types: orbital, valley, and spin. The…
The orbital, spin and valley degrees of freedom in silicon quantum dots support many modes of spin qubit operation. However, it is generally challenging to obtain information about the energy level spectrum over large ranges of parameter…
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…
Silicon-based metal-oxide-semiconductor quantum dots are prominent candidates for high-fidelity, manufacturable qubits. Due to silicon's band structure, additional low-energy states persist in these devices, presenting both challenges and…
The electrical control of single spin qubits based on semiconductor quantum dots is of great interest for scalable quantum computing since electric fields provide an alternative mechanism for qubit control compared with magnetic fields and…
We show that the mixing between spin and valley degrees of freedom in a silicon quantum bit (qubit) can be controlled by a static electric field acting on the valley splitting $\Delta$. Thanks to spin-orbit coupling, the qubit can be…
We measure the excited-state spectrum of a Si/SiGe quantum dot as a function of in-plane magnetic field, and we identify the spin of the lowest three eigenstates in an effective two-electron regime. The singlet-triplet splitting is an…
Although silicon is a promising material for quantum computation, the degeneracy of the conduction band minima (valleys) must be lifted with a splitting sufficient to ensure formation of well-defined and long-lived spin qubits. Here we…
An important challenge in silicon quantum electronics in the few electron regime is the potentially small energy gap between the ground and excited orbital states in 3D quantum confined nanostructures due to the multiple valley degeneracies…