A5012914150- Topological Materials and Phenomena
- Graphene research and applications
- 2D Materials and Applications
- Quantum Dots Synthesis And Properties
- Advanced Condensed Matter Physics
- Chalcogenide Semiconductor Thin Films
- Iron-based superconductors research
- Spectroscopy and Laser Applications
- Semiconductor Quantum Structures and Devices
- Photoacoustic and Ultrasonic Imaging
- Electronic and Structural Properties of Oxides
- Quantum and electron transport phenomena
- Spectroscopy Techniques in Biomedical and Chemical Research
- Domain Adaptation and Few-Shot Learning
- Magnetic and transport properties of perovskites and related materials
- Ga2O3 and related materials
- ZnO doping and properties
- Nanowire Synthesis and Applications
- Fullerene Chemistry and Applications
- Rare-earth and actinide compounds
- Fault Detection and Control Systems
- Quantum, superfluid, helium dynamics
- Terahertz technology and applications
- Advanced Chemical Physics Studies
- Conducting polymers and applications
Paul Scherrer Institute
2020-2024
Hong Kong University of Science and Technology
2022
University of Hong Kong
2022
ETH Zurich
2022
École Polytechnique Fédérale de Lausanne
2022
University of Oxford
2017-2020
Swiss Light Source
2020
Stanford University
2020
University of Florida
2020
ShanghaiTech University
2020
A new layered oxide semiconductor (Bi 2 O Se) is found with excellent electronic properties for promising applications.
Intrinsic defects such as vacancies, interstitials, and anti-sites often introduce rich luminescent properties in II−VI semiconductor nanomaterials. A clear understanding of the dynamics defect-related excitons is particularly important for design optimization nanoscale optoelectronic devices. In this paper, low-temperature steady-state time-resolved photoluminescence (PL) spectroscopies have been carried out to investigate emission cadmium sulfide (CdS) nanobelts that originates from...
Topological nodal semimetal (TNS), characterized by its touching conduction and valence bands, is a newly discovered state of quantum matter which exhibits various exotic physical phenomena. Recently, new type TNS called topological line (TNLS) predicted where band form degenerate one-dimension further protected crystal symmetry. In this work, we systematically investigated the bulk surface electronic structure non-symmorphic, TNLS in InBi (which also II Dirac semimetal) with strong...
Graphene has demonstrated great potential in new-generation electronic applications due to its unique properties such as large carrier Fermi velocity, ultrahigh mobility, and high material stability. Interestingly, the structures can be further engineered multilayer graphene by introduction of a twist angle between different layers create van Hove singularities (vHSs) at adjustable binding energy. In this work, using angle-resolved photoemission spectroscopy with sub-micrometer spatial...
Group VIII transition-metal dichalcogenides have recently been proposed to host type-II Dirac fermions. They are Lorentz-violating quasiparticles marked by a strongly tilted conic dispersion along certain momentum direction and therefore no analogs in the standard model. Using high-resolution angle-resolved photoemission spectroscopy, we systematically studied electronic structure of $\mathrm{PtS}{\mathrm{e}}_{2}$ full three-dimensional Brillouin zone. As predicted, pair crossings is...
Abstract Constrained by the Nielsen-Ninomiya no-go theorem, in all so-far experimentally determined Weyl semimetals (WSMs) points (WPs) always appear pairs momentum space with no exception. As a consequence, Fermi arcs occur on surfaces which connect projections of WPs opposite chiral charges. However, this situation can be circumvented case unpaired WP, without relevant surface arc connecting its projection, appearing singularly, while Berry curvature field is absorbed nontrivial charged...
Addressing the need for modulated spin configurations is crucial, as they serve foundational building blocks next-generation spintronics, particularly in atomically thin structures and at room temperature. In this work, we realize intrinsic ferromagnetism monolayer flakes tunable ferro-/antiferromagnetism (Fe0.56Co0.44)5GeTe2 antiferromagnets. Remarkably, ferromagnetic ordering (≥1 L) antiferromagnetic (≥4 remain discernible up to The TC (∼310 K) of sets a record high known exfoliated van...
Surface arcs (SAs) or Fermi connecting pairs of bulk Weyl points with opposite chiralities are the signatures semimetals in angle-resolved photoemission spectroscopy (ARPES) studies. The nontrivial topology band structure guarantees existence these exotic connectivity that is strongly dependent on surface. It has been theoretically proposed and experimentally confirmed at surfaces can complete an unusual closed cyclotron orbit called a orbit, which leads to various intriguing transport...
We have performed high-resolution angle-resolved photoemission spectroscopy of the ternary pnictide CaAuAs, which is predicted to be a three-dimensional topological Dirac semimetal (TDS). By accurately determining bulk-band structure, we revealed coexistence and quasi-two-dimensional Fermi surfaces with dominant hole carriers. The band structure around Brillouin-zone center characterized by an energy overlap between electron pockets, in excellent agreement first-principles band-structure...
Ultrafast optical-pump terahertz probe spectroscopy was performed over a graduated size distribution of CdS nanobelts to investigate the and surface effects on transient photoconductivity. It found that nanobelt has profound influence carrier localization photoconductivity dynamics, brought about by trapping at defects. The strong in is ascribed internal boundaries arising from depletion layer. increased thickness layer due continuous photocarriers defects results more pronounced after...
Abstract There is a growing recognition that electronic band structure local property of materials and devices, there steep growth in capabilities to collect the relevant data. New photon sources, from small-laboratory-based lasers free electron lasers, together with focusing beam optics advanced spectrometers, are beginning enable angle-resolved photoemission spectroscopy (ARPES) scanning mode spatial resolution near below microns, two- three orders magnitude smaller than what has been...
Co3Sn2S2 has been reported to be a Weyl semimetal with broken time-reversal symmetry c axis ferromagnetism (FM) below Curie temperature of 177 K. Despite the large interest in Co3Sn2S2, magnetic structure is still under debate and recent studies have challenged our understanding phase diagram by reporting unusual phases including presence exchange bias. Understanding magnetism important since its electronic band much-celebrated flat bands nodes depend on phase. In this work, using X-ray...
The authors present the surface plasmon effects of Au nanoparticles on photoluminescence properties ZnCdO/ZnO coaxial multiquantum-well nanowires fabricated using chemical vapor deposition and pulse laser methods. spontaneous emission rate from ZnCdO quantum wells was increased by coupling 1.29 times. strong between ZnO barriers provides an extra fast decay channel for excitons generated in barrier layer leads to exciton redistribution wells, which promotes radiative recombination but...
Two dimensional (2D) peak finding is a common practice in data analysis for physics experiments, which typically achieved by computing the local derivatives. However, this method inherently unstable when landscape complicated or signal-to-noise ratio of low. In work, we propose new tracking task formalized as an inverse problem, thus can be solved with convolutional neural network (CNN). addition, show that underlying principle experiments used to generate training data. By generalizing...
Weyl nodes can be classified into zero-dimensional (0D) points (WPs), 1D nodal lines (WNL) and 2D surfaces (WNS), which possess finite Chern numbers. Up to date, the largest number of WPs identified in semimetals is 4, thought a maximal value for linearly crossing solids. On other hand, whether numbers nonzero-dimensional linear objects have one upper limit still an open question. In this work, combining angle-resolved photoemission spectroscopy with density functional theory calculations,...
One material containing kagome bilayers and featuring both exceptional magnetism electron transport is the ferromagnetic metal Fe3Sn2. Notwithstanding widespread interest in Fe3Sn2, crystal twinning, difficulties distinguishing surface from bulk states, a large unit cell have until now prevented synchrotron-based spectroscopic observation of sharply resolved quasiparticles near Fermi which could be responsible for anomalous properties appearing at low temperatures material. Here we report...
Recently, commercially available copper foil has become an efficient and inexpensive catalytic substrate for scalable growth of large-area graphene films fundamental research applications. Interestingly, despite its hexagonal honeycomb lattice, can be grown into large aligned square-shaped sheets on foils. Here, by applying angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES) to study the three-dimensional electronic structures square foils, we verified...
Recent development in angle-resolved photoemission spectroscopy (ARPES) technique involves spatially resolving samples while maintaining the high-resolution feature of momentum space. This easily expands data size and its complexity for analysis, where one it is to label similar dispersion cuts map them spatially. In this work, we demonstrate that recent representational learning (self-supervised learning) model combined with k-means clustering can help automate part analysis save precious...
Optical-pump terahertz probe spectroscopy was used to investigate the size and surface effects on transient photoconductivity in CdS nanobelts. We found nanobelt has a profound influence carrier localization photoconductivity.
Optical-pump terahertz probe spectroscopy was used to investigate the size and surface effects on transient photoconductivity in CdS nanobelts. We found nanobelt has a profound influence carrier localization photoconductivity.
The coexistence of antiferromagnetic and ferromagnetic order at room temperature in single-phase van der Waals materials, particularly within the two-dimensional limit, has attracted significant research interest. Nonetheless, such materials are rare. In this work, we introduce an itinerant antiferromagnet (Fe0.56Co0.44)5GeTe2, where its exfoliated flakes remains discernible up to temperature, extending down monolayer limit. A notable phenomenon observed is evident odd-even layer-number...