Related papers: Extended interface states enhance valley splitting…
Spin and valley-orbit splittings are calculated in SiGe/Si/SiGe quantum wells (QWs) by using the tight-binding approach. In accordance with the symmetry considerations an existence of spin splitting of electronic states in perfect QWs with…
A novel type of shallow interface state in junctions of two semiconductors without band inversion is identified within the envelope function approximation, using the two-band model. It occurs in abrupt junctions when the interband velocity…
We report here a systematic study of the energy gaps at the odd-integer quantum Hall states $\nu=3$ and 5 under tilted magnetic (B) fields in a high quality Si two-dimensional electron system. Out of the coincidence region, the valley…
We examine the bound-state and free-state contributions to the density of states in a three-dimensional electron gas with a two-dimensional interface with Rashba spin-orbit coupling. Confinement of electrons to the interface is achieved…
Strain is extensively used to controllably tailor the electronic properties of materials. In the context of indirect band-gap semiconductors such as silicon, strain lifts the valley degeneracy of the six conduction band minima, and by…
Silicon-germanium heterostructures have successfully hosted quantum dot qubits, but the intrinsic near-degeneracy of the two lowest valley states poses an obstacle to high fidelity quantum computing. We present a modification to the Si/SiGe…
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…
Using magnetocapacitance data, we directly determine the chemical potential jump in a strongly correlated 2D electron system in silicon when the filling factor traverses the valley gap at \nu=1 and \nu=3. The data yield a valley gap that is…
We develop a weak coupling approach to superconductivity in twisted bilayer graphene, starting from the Fermi liquid regime. A key observation is that near half filling, the fermiology consists of well nested Fermi pockets derived from…
The coupling between $z$ valleys in the conduction band of a Si quantum well arises from phenomena occurring within several atoms from the interface, thus ruling out a theoretical description based on pure effective mass theory. However,…
SiC is set to enable a new era in power electronics impacting a wide range of energy technologies, from electric vehicles to renewable energy. Its physical characteristics outperform silicon in many aspects, including band gap, breakdown…
We report novel manifestation of the valley splitting for the two valley electron system in (100) Si-inversion layers at low carrier density. We found that valley splitting causes almost 100% modulation of the Shubnikov de Haas oscillations…
Previous works on deformed graphene predict the existence of valley-polarized states, however, optimal conditions for their detection remain challenging. We show that in the quantum Hall regime, edge-like states in strained regions can be…
Valley degrees of freedom, providing a novel way to increase capacity and efficiency of information processing, have become an important instrument for photonics. Experimental studies on photonic topological valley kink states at interfaces…
In Si quantum dot systems, large magnetic field gradients are needed to implement spin rotations via electric dipole spin resonance (EDSR). By increasing the effective electron dipole, flopping mode qubits can provide faster gates with…
Proposed Silicon-based quantum computer architectures have attracted attention because of their promise for scalability and their potential for synergetically utilizing the available resources associated with the existing infrastructure of…
A detailed understanding of the material properties that affect the splitting between the two low-lying valley states in Si/SiGe heterostructures will be increasingly important as the number of spin qubits is increased. Scanning gate…
We consider charge qubits based on shallow donor electron states in silicon and coupled quantum dots in GaAs. Specifically, we study the feasibility of P$_2^+$ charge qubits in Si, focusing on single qubit properties in terms of tunnel…
The valley splitting, which lifts the degeneracy of the lowest two valley states in a SiO$_2$/(100)Si/SiO$_2$ quantum well is examined through transport measurements. We demonstrate that the valley splitting can be observed directly as a…
We show that the merging of the spin- and valley-split Landau levels at the chemical potential is an intrinsic property of a strongly-interacting two-dimensional electron system in silicon. Evidence for the level merging is given by…