A5100317795- Topological Materials and Phenomena
- Graphene research and applications
- Iron-based superconductors research
- 2D Materials and Applications
- Quantum and electron transport phenomena
- Electronic and Structural Properties of Oxides
- Physics of Superconductivity and Magnetism
- Liquid Crystal Research Advancements
- Photonic and Optical Devices
- Magnetic and transport properties of perovskites and related materials
- GaN-based semiconductor devices and materials
- Photorefractive and Nonlinear Optics
- Advanced Condensed Matter Physics
- Atomic and Subatomic Physics Research
- Surface and Thin Film Phenomena
- Diamond and Carbon-based Materials Research
- MXene and MAX Phase Materials
- Magnetic properties of thin films
- Molecular Junctions and Nanostructures
- Nonlinear Optical Materials Research
- Advanced Fiber Laser Technologies
- Organic and Molecular Conductors Research
- Conducting polymers and applications
- Advanced Sensor and Energy Harvesting Materials
- Superconductivity in MgB2 and Alloys
Institute of Semiconductors
2024
Chinese Academy of Sciences
2024
University of Houston
2023
West Virginia University
2016-2023
Lanzhou University
2018
National Administration of Surveying, Mapping and Geoinformation of China
2018
University of Wisconsin–Milwaukee
2004-2016
Nanchong Central Hospital
2014
Combat Capabilities Development Command Soldier Center
2011
Chongqing University
2009
We report observation of holographic surface relief gratings with relatively large amplitude on a second order nonlinear optical polymeric material. Surface these polymer films were created upon exposure to polarized Ar+ laser beams at 488 nm without any subsequent processing steps. The structure the was investigated by atomic force microscopy. depth in typical case 120 which is approximately 20% original film thickness. diffraction efficiency gold-coated as function wavelength and...
A model for the formation of holographic surface relief gratings in azobenzene functionalized polymers is presented. Forces leading to migration polymer chains upon exposure light absorption band azo chromophore are attributed dipoles interacting with gradient electric field present material. Efficient trans–cis cycling azobenzenes allows cooperative movement chromophores under influence forces.
The recent observation of superconducting state at atomic scale has motivated the pursuit exotic condensed phases in two-dimensional (2D) systems. Here we report on a phase two-monolayer crystalline Ga films epitaxially grown wide band-gap semiconductor GaN(0001). This exhibits hexagonal structure and only 0.552 nm thickness, nevertheless, brings about transition temperature Tc as high 5.4 K, confirmed by situ scanning tunneling spectroscopy, ex electrical magneto-transport magnetization...
We have carried out two-beam interference experiments to form surface-relief gratings (SRGs) on azo polymer films under different polarization combinations. The mechanism of SRG formation azobenzene chromophore functionalized has been shown depend both the spatial variation intensity as well state incident field pattern. treatment presented in this paper clearly defines and distribution across region for configurations interfering beams. efficient photoisomerization process due optical...
Topological insulators (TIs) are promising for efficient spin-orbit torque (SOT) switching of ferromagnets due to spin-momentum locking their surface states. However, bulk-conducting channels limit full potential low-power operations. Here we synthesize bulk-insulating Bi2Se3 on (BiIn)2Se3/In2Se3 buffer layers by molecular beam epitaxy and compare SOT efficiency using Kerr rotation second harmonic Hall measurements. For Bi2Se3, find a 4-fold reduction in critical current density switch an...
The de Gennes extrapolation length is a direction dependent measure of the spatial evolution pairing gap near boundary superconductor, and thus provides viable means to probe its symmetry. It expected be infinite isotropic for plain s-wave pairing, finite anisotropic d-wave. Here, we synthesize single layer FeSe films on SrTiO3(001) (STO) substrates by molecular beam epitaxy, scanning tunneling microscopy/spectroscopy. We find 40% reduction superconducting specular [110]Fe edges, yielding an...
The spatial distributions of antibonding ${\ensuremath{\pi}}^{*}$ and ${\ensuremath{\sigma}}^{*}$ states in epitaxial graphene multilayers are mapped using electron energy-loss spectroscopy a scanning transmission microscope. Inelastic channeling simulations validate the interpretation spatially resolved signals terms electronic orbitals, demonstrate crucial effect material thickness on experimental capability to resolve distribution unoccupied states. This work illustrates current potential...
Quantum materials, particularly Dirac materials with linearly dispersing bands, can be effectively tuned by strain-induced lattice distortions leading to a pseudomagnetic field that strongly modulates their electronic properties. Here, we grow kagome magnet FeSn films, consisting of alternatingly stacked Sn2 honeycomb (stanene) and Fe3Sn layers, on SrTiO3(111) substrates molecular beam epitaxy. Using scanning tunneling microscopy/spectroscopy, show the Sn layer periodically deformed...
van der Waals (vdW) heterostructures of two-dimensional materials exhibit properties and functionalities that can be tuned by stacking order interlayer coupling. Although direct covalent bonding is not expected at the heterojunction, formation an interface nevertheless breaks symmetries layers, orthogonal requirement wave functions lead to indirect interfacial coupling, creating new beyond their constituent layers. Here, we fabricate graphene/topological insulator vdW heterostructure...
Abstract The discovery of high-temperature superconductivity in single layer FeSe epitaxially grown on SrTiO 3 (001) substrates has instigated extensive debate over whether its pairing symmetry is conventional sign-preserving s -wave or unconventional sign-changing. Here, we probe the state for FeSe/SrTiO by molecular beam epitaxy using scanning tunneling microscopy/spectroscopy. We observe robust in-gap bound states induced non-magnetic Fe-vacancy defects within Fe-plane, which exhibit...
Kagome lattice hosts a plethora of quantum states arising from the interplay topology, spin-orbit coupling, and electron correlations. Here, we report symmetry-breaking electronic orders tunable by an applied magnetic field in model magnet FeSn consisting alternating stacks two-dimensional Fe3Sn Sn2 honeycomb layers. On layer terminated thin films epitaxially grown on SrTiO3(111) substrates, observe trimerization using scanning tunneling microscopy/spectroscopy, breaking its six-fold...
Abstract The capability of controlling superconductivity by light is highly desirable for active quantum device applications. Since superconductors rarely exhibit strong photoresponses, and optically sensitive materials are often not superconducting, efficient coupling between these two characters can be very challenging in a single material. Here we show that, FeSe/SrTiO 3 heterostructures, the superconducting transition temperature FeSe monolayer effectively raised interband...
Scanning tunneling microscopy (STM) is a powerful technique for imaging atomic structure and inferring information on local elemental composition, chemical bonding, electronic excitations. However, plain visual analysis of STM images can be challenging such determination in multicomponent alloys, particularly beyond the diluted limit due to disorder inhomogeneity. One viable solution use machine learning analyze data identify hidden patterns correlations. Here, we apply this approach...
Using migration enhanced molecular beam epitaxy, we synthesize single- and bilayer ${\mathrm{WSe}}_{2}$ on epitaxial graphene/SiC(0001) investigate the electronic properties of their edges with different terminations using scanning tunneling microscopy/spectroscopy (STM/S). Density functional theory calculations predict edge states at both Se W edges, whose position spatial distribution depend how are terminated. STS reveals that whether nominal detectable depends number additional Se,...
Triboelectric nanogenerators were fabricated using organic semiconductor CuPc. With 10 wt% iodine doping, the devices showed an excellent performance with a voltage output of 300 V, current density 110 mA m −2 , and power 8.68 W .
Two-dimensional (2D) magnets exhibit unique physical properties for potential applications in spintronics. To date, most 2D ferromagnets are obtained by mechanical exfoliation of bulk materials with van der Waals interlayer interactions, and the synthesis single- or few-layer strong coupling remains experimentally challenging. Here, we report epitaxial growth non-van ferromagnetic bilayer FeSb on SrTiO3(001) substrates stabilized to substrate, which exhibits in-plane magnetic anisotropy a...
Abstract Superconducting radio-frequency (SRF) resonator cavities provide extremely high quality factors > 10 at 1–2 GHz and 2 K in large linear accelerators of high-energy particles. The maximum accelerating field SRF is limited by penetration vortices into the superconductor. Present state-of-the-art Nb can withstand up to 50 MV/m gradients magnetic fields 200–240 mT which destroy low-dissipative Meissner state. Achieving higher requires superconductors with thermodynamic critical...
Surface relief gratings (SRG) on films of azobenzene–modified cellulose (azocellulose) with ultrahigh molecular weight were holographically recorded in a single step. modulation depth the SRGs increased degree substitution (DS) azobenzene chromophores as well grating spacing. Large surface modulations over 500 nm all samples obtained spacing 4 μm. A linear increase photoinduced birefringence chromophore concentration these photodynamic polymers was also observed. The maximum 0.11 achieved...
The sensitive dependence of monolayer materials on their environment often gives rise to unexpected properties. It was recently demonstrated that FeSe a SrTiO$_3$ substrate exhibits much higher superconducting critical temperature T$_C$ than the bulk material. Here, we examine interfacial structure / and effect an Ti$_{1+x}$O$_2$ layer increased using combination scanning transmission electron microscopy density functional theory. We find forms its own quasi-two-dimensional layer, bonding...
Grain boundaries (GBs) are inherent extended defects in chemical vapor deposited (CVD) transition metal dichalcogenide (TMD) films. Characterization of the atomic structure and electronic properties these GBs is crucial for understanding controlling TMDs via defect engineering. Here, we report CVD grown MoS2 on epitaxial graphene/SiC(0001). Using scanning tunneling microscopy/spectroscopy, find that mostly consist arrays dislocation cores, where presence mid-gap states shifts both conduction...