We investigate how a magnetic field induces one-dimensional edge channels when the two-dimensional surface states of three-dimensional topological insulators become gapped. The Hall effect, measured by contacting those channels, remains quantized even in situations where the θ term in the bulk and the associated surface Hall conductivities, σ(xy)(S), are not quantized due to the breaking of time-reversal symmetry. The quantization arises as the θ term changes by ±2πn along a loop around n edge channels. Model calculations show how an interplay of orbital and Zeeman effects leads to quantum Hall transitions, where channels get redistributed along the edges of the crystal. The network of edges opens new possibilities to investigate the coupling of edge channels.
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http://dx.doi.org/10.1103/PhysRevLett.108.126807 | DOI Listing |
J Neural Eng
January 2025
Mechanical and Aerospace, Missouri University of Science and Technology, 400 W 13th St., Rolla, Missouri, 65409, UNITED STATES.
This work explores use of a few-shot transfer learning method to train and implement a convolutional spiking neural network (CSNN) on a BrainChip Akida AKD1000 neuromorphic system-on-chip for developing individual-level, instead of traditionally used group-level, models using electroencephalographic data. The efficacy of the method is studied on an advanced driver assist system related task of predicting braking intention. \emph{Approach}: Data are collected from participants operating an NVIDIA JetBot on a testbed simulating urban streets for three different scenarios.
View Article and Find Full Text PDFEnviron Res
January 2025
College of Environmental Science and Engineering, Hunan University, Changsha 410082, P.R. China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, P.R. China. Electronic address:
Internal nutrient cycling, especially phosphorus (P), is of great influence in lake eutrophication. Dissolved organic matter (DOM) and microorganisms are ubiquitous in the sediments and closely associated with P-cycling. However, the underlying interactions of DOM, microorganisms and P in floodplain lake area with different hydrological characteristics remain scarce.
View Article and Find Full Text PDFNanotechnology
January 2025
Electronic Sci.&Eng., Xi'an Jiaotong University, 28 Xianning West Road,Beilin District, Xi 'an, Shaanxi Province, China, Xi'an, 710049, CHINA.
The accurate estimation of the temperature distribution of the GaN based power devices and optimization of the device structure is of great significance to possibly solve the self-heating problem, which hinders the further enhancement of the device performances. We present here the operando temperature measurement with high spatial resolution using Raman spectroscopy of AlGaN/GaN high electron mobility transistors (HEMTs) with different device structures and explore the optimization of the device thermal design accordingly. The lateral and depth temperature distributions of the single-finger HEMT were characterized.
View Article and Find Full Text PDFScientific-grade spectrometers with high hyperspectral resolution and high spectral accuracy are desirable in miniaturized optical systems to maintain stable and real-time spectral sampling. Fourier transform spectrometers that utilize high-precision moving mirrors generally struggle to enhance their miniaturization and stable real-time performance. A static infrared spectral measurement method is proposed that uses micro/nano-optical devices as the core of static interference and lightweight imaging.
View Article and Find Full Text PDFNat Commun
January 2025
National Key Laboratory of Uranium Resource Exploration-Mining and Nuclear Remote Sensing, East China University of Technology, Nanchang, 330013, China.
Piezoelectric catalysis possesses the potential to convert ocean wave energy into and holds broad prospects for extracting uranium from seawater. Herein, the Z-type ZnO@COF heterostructure composite with excellent piezoelectric properties was synthesized through in situ growth of covalent organic frameworks (COFs) on the surface of ZnO and used for efficient uranium extraction. The designed COFs shell enables ZnO with stability, abundant active sites and high-speed electron transport channels.
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