We study theoretically current quantization in the charge turnstile based on the superconductor-normal-metal single-electron transistor. The quantization accuracy is limited by either Andreev reflection or by Cooper-pair-electron cotunneling. The rates of these processes are calculated in the "above-the-threshold" regime when they compete directly with the lowest-order tunneling. By shaping the ac gate voltage drive it should be possible to achieve the metrological accuracy of 10;{-8}, while maintaining the quantized current on the level of 30 pA, just by one turnstile with realistic parameters using aluminum as a superconductor.
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http://dx.doi.org/10.1103/PhysRevLett.101.066801 | DOI Listing |
Materials (Basel)
September 2024
Faculty of Technical Physics, Information Technology and Applied Mathematics, Institute of Physics, Lodz University of Technology, 93-005 Lodz, Poland.
A derivation of a tight-binding model from Schrödinger formalism for various topologies of position-based semiconductor qubits is presented in the case of static and time-dependent electric fields. The simplistic tight-binding model enables the description of single-electron devices at a large integration scale. The case of two electrostatically Wannier qubits (also known as position-based qubits) in a Schrödinger model is presented with omission of spin degrees of freedom.
View Article and Find Full Text PDFNanotechnology
October 2024
Instituto de Física Teórica, São Paulo State University, São Paulo, Brasil.
Carbon-based nanostructures have unparalleled electronic properties. At the same time, using an allotrope of carbon as the contacts can yield better device control and reproducibility. In this work, we simulate a single-electron transistor composed of a segment of a graphene nanoribbon coupled to carbon nanotubes electrodes.
View Article and Find Full Text PDFNano Lett
October 2024
CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China.
Modern quantum device fabrication often requires precisely adding and removing materials at nanoscales, which is challenging for high-quality correlated oxide devices. In this work, we present a novel nanofabrication method that remotely controls the interfacial metal-insulator transition at the LaAlO/SrTiO interface by selectively removing an LaAlO overlayer using a diamond tip. Remarkably, we observe a large force window within which single atomic layer precision of control is achievable.
View Article and Find Full Text PDFRev Sci Instrum
August 2024
Department of Physics, McGill University, Montréal, Québec H3A 2T8, Canada.
The ongoing development of single electron, nano-, and atomic scale semiconductor devices would greatly benefit from a characterization tool capable of detecting single electron charging events with high spatial resolution at low temperatures. In this work, we introduce a novel Atomic Force Microscope (AFM) instrument capable of measuring critical device dimensions, surface roughness, electrical surface potential, and ultimately the energy levels of quantum dots and single electron transistors in ultra miniaturized semiconductor devices. The characterization of nanofabricated devices with this type of instrument presents a challenge: finding the device.
View Article and Find Full Text PDFNanoscale Adv
August 2024
Laboratory for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology Yokohama 226-8503 Japan
Semiconductor quantum dots (QDs) have unique discrete energy levels determined by the particle size and material. Therefore, they have potential applications as novel optical and electronic devices. Among those, colloidal group II-VI semiconductor quantum dots stand out for their facile synthesis and band gaps aligned with the visible light spectrum.
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