Related papers: Depletion-mode Quantum Dots in Intrinsic Silicon
Reliable detection of single electron tunneling in quantum dots (QD) is paramount to use this category of device for quantum information processing. Here, we report charge sensing in a degenerately phosphorus-doped silicon QD by means of a…
We review recent transport experiments that reveal two-threshold voltage-current characteristics, marked by a significant increase in noise between the two threshold voltages, at low electron densities in the insulating regime in…
We report on the effects of a global top gate on low-frequency noise in Schottky gate-defined quantum point contacts (QPCs) and quantum dots (QDs) in a modulation-doped Si/SiGe heterostructure. For a relatively large top gate voltage, the…
We report on the fabrication and characterization of patterned high-mobility two-dimensional electron gases (2DEG) formed on SrTiO$_3$ (STO) substrate surfaces by hydrogen plasma exposure. The resulting devices consistently showed high…
Conveyor-mode shuttling is a key approach for implementing intermediate-range coupling between electron-spin qubits in quantum dots. Initial implementations are encouraging; however, long shuttling trajectories are guaranteed to encounter…
We demonstrate double quantum dots fabricated in undoped Si/SiGe heterostructures relying on a double top-gated design. Charge sensing shows that we can reliably deplete these devices to zero charge occupancy. Measurements and simulations…
We have incorporated an aluminum single electron transistor directly into the defining gate structure of a semiconductor quantum dot, permitting precise measurement of the charge in the dot. Voltage biasing a gate draws charge from a…
The structural and electronic properties of amorphous silicon ($a$-Si) are investigated by first-principles calculations based on the density-functional theory (DFT), focusing on the intrinsic structural defects. By simulated melting and…
We investigate the long-standing problem of the hole localization at the Al impurity in quartz SiO$_2$, using a relatively recent DFT hybrid-functional method in which the exchange fraction is obtained \emph{ab initio}, based on an analogy…
Quantum dots are artificial atoms used for a multitude of purposes. Charge defects are commonly present and can significantly perturb the designed energy spectrum and purpose of the dots. Voltage controlled exchange energy in silicon double…
Spherical shaped Si quantum dots (QDs) embedded into the SiO2 substrate are considered in the single sub-band effective mass approach. Nonparabolicity of the Si conduction band is described by the energy dependence of electron effective…
The quantum harmonic oscillator (QHO), one of the most important and ubiquitous model systems in quantum mechanics, features equally spaced energy levels or eigenstates. Here we present a new class of nearly ideal QHOs formed by hydrogenic…
Semiconductor spin qubits have gained increasing attention as a possible platform to host a fault-tolerant quantum computer. First demonstrations of spin qubit arrays have been shown in a wide variety of semiconductor materials. The highest…
The properties of an exciton in a type II quantum dot are studied under the influence of a perpendicular applied magnetic field. The dot is modelled by a quantum disk with radius $R$, thickness $d$ and the electron is confined in the disk,…
We present gate-controlled single, double, and triple dot operation in electrostatically gapped bilayer graphene. Thanks to the recent advancements in sample fabrication, which include the encapsulation of bilayer graphene in hexagonal…
Two-dimensional electron or hole systems in semiconductors offer the unique opportunity to investigate the physics of strongly interacting fermions. We have measured the 1/f resistance noise of two-dimensional hole systems in high mobility…
We define single quantum dots of lengths varying from 60 nm up to nearly half a micron in Ge-Si core-shell nanowires. The charging energies scale inversely with the quantum dot length between 18 and 4 meV. Subsequently, we split up a long…
Studies of different experimental groups that explore the properties of a two-dimensional electron gas in silicon semiconductor systems ((100) Si metal-oxide-semiconductor field-effect transistors (MOSFETs) and (100) SiGe/Si/SiGe quantum…
We study two quantum dots in the limit of strong dot-lead coupling and weak dot-dot tunneling. The model maps on Ising-coupled Kondo impurities. We argue that a new quantum critical fixed point exists at an intermediate value of the mutual…
The coherent tunnelling of Cooper pairs across Josephson junctions (JJs) generates a nonlinear inductance that is used extensively in quantum information processors based on superconducting circuits, from setting qubit transition…