A5061062315- Topological Materials and Phenomena
- Graphene research and applications
- Advanced Condensed Matter Physics
- 2D Materials and Applications
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Electronic and Structural Properties of Oxides
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Iron-based superconductors research
- Rare-earth and actinide compounds
- Quantum many-body systems
- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- ZnO doping and properties
- Surface and Thin Film Phenomena
- Magnetic properties of thin films
- Molecular Junctions and Nanostructures
- Cold Atom Physics and Bose-Einstein Condensates
- Surface Chemistry and Catalysis
- GaN-based semiconductor devices and materials
- Semiconductor Quantum Structures and Devices
- Organic and Molecular Conductors Research
- Adhesion, Friction, and Surface Interactions
Shanghai Jiao Tong University
2016-2025
Hefei University
2023-2025
Korea University
2024
Chongqing University of Science and Technology
2024
Beijing Academy of Quantum Information Sciences
2023
Argonne National Laboratory
2009-2023
Shanghai International Studies University
2023
University of Chinese Academy of Sciences
2020-2022
Collaborative Innovation Center of Advanced Microstructures
2015-2022
Institute of Psychology, Chinese Academy of Sciences
2020
Weyl physics emerges in the laboratory fermions—massless particles with half-integer spin—were once mistakenly thought to describe neutrinos. Although not yet observed among elementary particles, fermions may exist as collective excitations so-called semimetals. These materials have an unusual band structure which linearly dispersing valence and conduction bands meet at discrete “Weyl points.” Xu et al. used photoemission spectroscopy identify TaAs a semimetal capable of hosting fermions. In...
Abstract Topological semimetals can support one-dimensional Fermi lines or zero-dimensional Weyl points in momentum space, where the valence and conduction bands touch. While degeneracy are robust against any perturbation that preserves translational symmetry, nodal require protection by additional crystalline symmetries such as mirror reflection. Here we report, based on a systematic theoretical study detailed experimental characterization, existence of topological nodal-line states...
Abstract Weyl semimetals provide the realization of fermions in solid-state physics. Among all physical phenomena that are enabled by semimetals, chiral anomaly is most unusual one. Here, we report signatures magneto-transport measurements on first semimetal TaAs. We show negative magnetoresistance under parallel electric and magnetic fields, is, unlike metals whose resistivity increases an external field, observe our high mobility TaAs samples become more conductive as a field applied along...
Magnetic Weyl semimetals (WSMs)—materials that host exotic quasiparticles called fermions—must break either spatial inversion or time-reversal symmetry. A number of WSMs symmetry have been identified, but showing unambiguously a material is time-reversal-breaking WSM tricky. Three groups now provide spectroscopic evidence for this latter state in magnetic materials (see the Perspective by da Silva Neto). Belopolski et al. probed Co 2 MnGa using angle-resolved photoemission spectroscopy,...
Weyl semimetals are expected to open up new horizons in physics and materials science because they provide the first realization of fermions exhibit protected Fermi arc surface states. However, had been found be extremely rare nature. Recently, a family compounds, consisting tantalum arsenide, phosphide (TaP), niobium phosphide, was predicted as semimetal candidates. We experimentally realize state TaP. Using photoemission spectroscopy, we directly observe fermion cones nodes bulk, arcs on...
We identify a Weyl semimetal state in an inversion breaking, stoichiometric compound strontium silicide, SrSi$_2$, with many new and novel properties that are distinct from the TaAs family. theoretically show SrSi$_2$ is even without spin-orbit coupling that, after inclusion of coupling, two fermions stick together forming exotic double fermion quadratic dispersions higher chiral topological charge 2. Moreover, we find nodes opposite charges located at different energies due to absence...
A topological nodal-line semimetal is a state of matter with one-dimensional bulk nodal lines and two-dimensional so-called drumhead surface bands. Based on first-principles calculations an effective $\mathbit{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbit{p}$ model, we theoretically propose the existence fermions in ternary transition-metal chalcogenide ${\mathrm{TlTaSe}}_{2}$. The noncentrosymmetric structure strong spin-orbit coupling give rise to spinful states which are protected...
Weyl semimetals may open a new era in condensed matter physics because they provide the first example of fermions, realize topological classification even though system is gapless, exhibit Fermi arc surface states and demonstrate chiral anomaly other exotic quantum phenomena. So far, only known are TaAs class materials. Here, we propose existence tunable metallic state Mo$_x$W$_{1-x}$Te$_2$ via our first-principles calculations. We that 2% Mo doping sufficient to stabilize metal not at low...
In quantum field theory, Weyl fermions are relativistic particles that travel at the speed of light and strictly obey celebrated Lorentz symmetry. Their low-energy condensed matter analogs semimetals, which conductors whose electronic excitations mimic fermion equation motion. Although traditional (type I) emergent observed in TaAs still approximately respect symmetry, recently, so-called type II semimetal has been proposed, where quasiparticles break symmetry so strongly they cannot be...
Here we report the evidence of type II Dirac Fermion in layered crystal PdTe2. The de Haas-van Alphen oscillations find a small Fermi pocket with cross section 0.077nm-2 nontrivial Berry phase. First-principal calculations reveal that it is originated from hole tilted cone. Angle Resolved Photoemission Spectroscopy demonstrates cone featured dispersion. We also suggest PdTe2 an improved platform to host topological superconductors.
Abstract The recent discovery of a Weyl semimetal in TaAs offers the first fermion observed nature and dramatically broadens classification topological phases. However, it has proven challenging to study rich transport phenomena arising from emergent fermions. series Mo x W 1− Te 2 are inversion-breaking, layered, tunable semimetals already under as promising platform for new electronics recently proposed host Type II, or strongly Lorentz-violating, Here we report at =25%. We use pump-probe...
Topological semimetals (TSMs) including Weyl and nodal-line are expected to open the next frontier of condensed matter materials science. Although first inversion breaking semimetal was recently discovered in TaAs, its magnetic counterparts, i.e., time-reversal nodal line semimetals, remain elusive. They predicted exhibit exotic properties distinct from TSMs TaAs. In this paper, we identify topological state ferromagnetic half-metal compounds Co$_2$TiX (X=Si, Ge, or Sn) with Curie...
Weyl semimetals are novel topological conductors that host fermions as emergent quasiparticles. In this Rapid Communication, we propose a new type of semimetal state breaks both time-reversal symmetry and inversion in the $R\mathrm{AlGe}$ ($R=\mathrm{rare}\ensuremath{-}\mathrm{earth}$) family. Compared to previous predictions magnetic candidates, prediction nodes is more robust less dependent on details magnetism because generated already by breaking ferromagnetism acts simple Zeeman...
CsV${}_{3}$Sb${}_{5}$ has been recently discovered to be a kagome superconductor. Here, the authors use scanning tunneling microscopy study its charge order and superconductivity at atomic scale. Through mapping energy gap of order, identify chiral electronic nature. They also elucidate surface nature 1$\ifmmode\times\else\texttimes\fi{}$4 superlattice superconducting excitations.
The emergence of spinon quasiparticles, which carry spin but lack charge, is a hallmark collective quantum phenomena in low-dimensional systems. While the existence spinons has been demonstrated through scattering spectroscopy ensemble samples, real-space imaging these quasiparticles within individual chains remained elusive. In this study, we construct Heisenberg antiferromagnetic spin-1/2 using open-shell [2]triangulene molecules as building blocks. Each unit, owing to its sublattice...
The selective adsorption of two different types particles to a patterned surface is shown for thiol-modified gold. far end the alkanethiols chemically varied and binds polymer with properties—as illustrated in Figure charged composition size. Tuning hydrophobicity hydrogen bonding this manner provides versatile route composite colloidal structures.
The recent discovery of the first Weyl semimetal in TaAs provides observation a fermion nature and demonstrates novel type anomalous surface state, Fermi arc. Like topological insulators, bulk invariants are uniquely fixed by states sample. Here we present set distinct conditions, accessible angle-resolved photoemission spectroscopy (ARPES), each which arcs state band structure, with minimal reliance on calculation. We apply these results to NbP. For time, rigorously demonstrate nonzero...
Femtosecond midinfrared pulses are used to directly excite the lattice of single-layer manganite La${}_{0.5}$Sr${}_{1.5}$MnO${}_{4}$. Magnetic and orbital orders, as measured by femtosecond resonant soft x-ray diffraction with an free-electron laser, reduced within a few picoseconds. This effect is interpreted displacive exchange quench, prompt shift in equilibrium value magnetic- orbital-order parameters after has been distorted. Control magnetism through ultrafast excitation may be use for...
The family of binary compounds including TaAs, TaP, NbAs, and NbP was recently discovered as the first realization Weyl semimetals. In order to develop a comprehensive description charge carriers in these semimetals, we performed systematic electronic structure calculations which reveal nature Fermi surfaces their complex interconnectivity NbP. Our work report comparative study surface topology band details all known members semimetal provide necessary building blocks for advancing our...
Topological metals and semimetals (TMs) have recently drawn significant interest. These materials give rise to condensed matter realizations of many important concepts in high-energy physics, leading wide-ranging protected properties transport spectroscopic experiments. The most studied TMs, i.e., Weyl Dirac semimetals, feature quasiparticles that are direct analogues the textbook elementary particles. Moreover, TMs known so far can be characterized based on dimensionality band crossing....
Members of the Mo${}_{x}$W${}_{1-x}$Te${}_{2}$ series are predicted to be Weyl semimetals, hosting type-II fermions, which have yet experimentally realized and unusual because they strongly violate Lorentz invariance. Crucially, points in this system sit above Fermi level. Here, authors show that for a cone, although not type-I if point is level, then it's necessary see band structure level observe topological arc. The also discover pump-probe angle-resolved photoemission beautifully...
A Weyl semimetal is a new state of matter that hosts fermions as quasiparticle excitations. The at zero energy correspond to points bulk-band degeneracy, called nodes, which are separated in momentum space and connected only through the crystal's boundary by an exotic Fermi arc surface state. We experimentally measure spin polarization arcs first discovered TaAs. Our data, for time, reveal arcs' spin-polarization magnitude large 80% lies completely plane surface. Moreover, we demonstrate...