Atomistic tight-binding (TB) simulations are performed to calculate the Stark shift of the hyperfine coupling for a single arsenic (As) donor in silicon (Si). The role of the central-cell correction is studied by implementing both the static and the non-static dielectric screenings of the donor potential, and by including the effect of the lattice strain close to the donor site. The dielectric screening of the donor potential tunes the value of the quadratic Stark shift parameter (η2) from -1.3 × 10(-3) µm(2) V(-2) for the static dielectric screening to -1.72 × 10(-3) µm(2) V(-2) for the non-static dielectric screening. The effect of lattice strain, implemented by a 3.2% change in the As-Si nearest-neighbour bond length, further shifts the value of η2 to -1.87 × 10(-3) µm(2) V(-2), resulting in an excellent agreement of theory with the experimentally measured value of -1.9 ± 0.2 × 10(-3) µm(2) V(-2). Based on our direct comparison of the calculations with the experiment, we conclude that the previously ignored non-static dielectric screening of the donor potential and the lattice strain significantly influence the donor wave function charge density and thereby leads to a better agreement with the available experimental data sets.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1088/0953-8984/27/15/154207 | DOI Listing |
Nanomaterials (Basel)
December 2024
High-Power Converter Systems (HLU), Technical University of Munich (TUM), 80333 Munich, Germany.
In this paper, a new label-free DNA nanosensor based on a top-gated (TG) metal-ferroelectric-metal (MFM) graphene nanoribbon field-effect transistor (TG-MFM GNRFET) is proposed through a simulation approach. The DNA sensing principle is founded on the dielectric modulation concept. The computational method employed to evaluate the proposed nanobiosensor relies on the coupled solutions of a rigorous quantum simulation with the Landau-Khalatnikov equation, considering ballistic transport conditions.
View Article and Find Full Text PDFBiosensors (Basel)
November 2024
Nano Electrochemistry Laboratory, College of Engineering, University of Georgia, Athens, GA 30602, USA.
Hepatitis A virus (HAV), a major cause of acute liver infections, is transmitted through the fecal-oral route and close contact with infected individuals. Current HAV standardized methods rely on the detection of virus antigen or RNA, which do not differentiate between infectious and non-infectious HAV. The objective of this study was to develop a prototype cell-based electrochemical biosensor for detection of infectious HAV.
View Article and Find Full Text PDFNano Lett
December 2024
Wyant College of Optical Sciences, University of Arizona, 1630 East University Boulevard, Tucson, Arizona 85721, United States.
Microscopic many-body models based on inputs from first-principles density functional theory are used to calculate the carrier losses due to free carrier Auger-Meitner recombination (AMR) processes in Mo- and W-based monolayer transition metal dichalcogenides as a function of the carrier density, temperature, and dielectric environment. Despite the exceptional strength of Coulomb interaction in the two-dimensional materials, the AMR losses are found to be similar in magnitude to those in conventional III-V-based quantum wells for the same wavelengths. Unlike the case in III-V materials, the losses show nontrivial density dependencies due to the fact that bandgap renormalizations on the order of hundreds of millielectronvolts can bring higher bands into or out of resonance with the optimal energy level for the AMR transition, approximately one bandgap from the lowest band.
View Article and Find Full Text PDFTalanta
December 2024
Nextgen Adaptive Systems Group, Department of Electrical Engineering, National Institute of Technology Patna, Bihar, India. Electronic address:
This study explores a quick, low-cost method to detect Alzheimer's disease (AD) by evaluating the accomplishment of a Gate-Stack (GS) Field Effect Transistor (FET). We investigate Single-Metal (SM), Dual-Metal (DM), and Tri-Metal Double Gate (DG) configurations, where cavities have been created by etching the oxide layer underneath the gate to immobilize grey matter samples collected through Solid-phase microextraction (SPME). Healthy and AD-affected grey matter have different dielectric characteristics at high frequencies.
View Article and Find Full Text PDFMethodsX
December 2024
Department of Electrical Engineering, College of Engineering Al-Hussein Bin Talal, University, Ma'an 71111, Jordan.
Coplanar waveguide (CPW) transmission lines are valued for their planar design, low radiation, and minimized signal loss, but controlling their characteristic impedance remains a challenge. This study employs the Taguchi method, a statistical approach, to optimize the characteristic impedance by adjusting eight control factors: track width, track thickness, gap width, dielectric height, backplane thickness, conductor material conductivity, dielectric conductivity, and operational frequency. The analysis evaluates these factors across three levels to find optimal conditions, with dielectric height and track width identified as most influential.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!