A5100353297- Topological Materials and Phenomena
- Graphene research and applications
- Advanced Condensed Matter Physics
- 2D Materials and Applications
- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Electronic and Structural Properties of Oxides
- Rare-earth and actinide compounds
- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Advanced Thermoelectric Materials and Devices
- Quantum and electron transport phenomena
- Quantum many-body systems
- Cold Atom Physics and Bose-Einstein Condensates
- Heusler alloys: electronic and magnetic properties
- Ga2O3 and related materials
- GaN-based semiconductor devices and materials
- Corporate Taxation and Avoidance
- Quantum Dots Synthesis And Properties
- Advanced NMR Techniques and Applications
- Intellectual Capital and Performance Analysis
- Atomic and Subatomic Physics Research
- MXene and MAX Phase Materials
- Quantum Mechanics and Non-Hermitian Physics
- Diamond and Carbon-based Materials Research
Southern University of Science and Technology
2015-2024
Renmin University of China
2019-2024
Northeast Normal University
2024
Fudan University
2024
Anhui University
2023
University of California System
2023
Tsinghua University
2022-2023
Beijing Academy of Quantum Information Sciences
2022-2023
Shandong University
2023
Hong Kong University of Science and Technology
2023
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...
Nailing down the topology of a semimetal Topological insulators are exotic materials that have conducting surface state can withstand certain types material imperfection. Theoreticians predicted different kind in related three-dimensional topological Dirac semimetals, which do not an energy gap band structure bulk. Xu et al. used photoemission spectroscopy to map out Na 3 Bi and detected state. Their results may lead further insights into physics matter. Science , this issue p. 294
Lower-cost thermoelectrics Thermoelectric materials convert heat to electricity, making them attractive for harvesting or cooling applications. However, many high-performance are made of expensive toxic materials. He et al. found that a material composed primarily tin and sulfur could be optimized have relatively good thermoelectric properties. Introducing about 10% selenium sulfide helped tune these properties by electronic band manipulation. This is step toward more earth-abundant, less...
The recent discovered antiferromagnetic topological insulators in Mn-Bi-Te family with intrinsic magnetic ordering have rapidly drawn broad interest since its cleaved surface state is believed to be gapped, hosting the unprecedented axion states half-integer quantum Hall effect. Here, however, we show unambiguously by using high-resolution angle-resolved photoemission spectroscopy that a gapless Dirac cone at (0001) of MnBi$_2$Te$_4$ exists between bulk band gap. Such unexpected remains...
We use angle resolved photoemission spectroscopy to study the momentum dependence of superconducting gap in NdFeAsO0.9F0.1 single crystals. find that Gamma hole pocket is fully gapped below transition temperature. The value 15+/-1.5 meV and its anisotropy around smaller than 20% this value-consistent with an isotropic or anisotropic s-wave symmetry order parameter. This a significant departure from situation cuprates, pointing possibility superconductivity iron arsenic based system arises...
We use angle-resolved photoemission spectroscopy to investigate the electronic properties of newly discovered iron-arsenic superconductor ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{K}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ and nonsuperconducting ${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$. Our study indicates that Fermi surface undoped, parent compound ${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$ consists hole pocket(s) at $\ensuremath{\Gamma}$ (0,0) larger electron $X$ (1,0), in general agreement with...
By combining transport and photoemission measurements on (Bi(1-x)In(x))(2)Se(3) thin films, we report that this system transforms from a topologically nontrivial metal into trivial band insulator through three quantum phase transitions. At x ≈ 3%-7%, there is transition to metal. 15%, the becomes variable-range-hopping insulator. Finally, above 25%, true with its resistance immeasurably large even at room temperature. This material provides new venue investigate tunable physics devices...
Using angle-resolved photoemission spectroscopy, we report electronic structure for representative members of ternary topological insulators. We show that several this family, such as Bi2Se2Te, Bi2Te2Se, and GeBi2Te4, exhibit a singly degenerate Dirac-like surface state, while Bi2Se2S is fully gapped insulator with no measurable state. One these compounds, shows tunable state dispersion upon its alloying Sb (SbxBi2-xSe2Te series). Other the family GeBi2Te4 BiTe1.5S1.5 an in-gap Dirac point,...
We used angle resolved photoemission spectroscopy and thermoelectric power to study the poorly explored, highly overdoped side of phase diagram Ba(Fe1-xCox)2As2 high temperature superconductor. Our data demonstrate that several Lifshitz transitions - topological changes Fermi surface occur for large x. Tc starts decrease with doping when cylindrical, central hole pocket ellipsoids centering at Z point, goes zero before these disappear around x = 0.2. Changes in similar x-values. Beyond this...
The interaction between light and novel two-dimensional electronic states holds promise to realize new fundamental physics optical devices. Here, we use pump-probe photoemission spectroscopy study the optically-excited Dirac surface in bulk-insulating topological insulator Bi2Te2Se, reveal properties that are sharp contrast those of bulk-metallic insulators. We observe a gigantic life-time exceeding 4 micro-sec for whereas most insulators such as Bi2Se3 has been limited few picoseconds....
Abstract The topological surface states of magnetic systems, such as Weyl semimetals and axion insulators, are associated with unconventional transport properties nonzero or half-quantized anomalous Hall effect. Here we study the effect its spectral signatures in different phases using both model Hamiltonian first-principles calculations. We demonstrate that by tailoring magnetization interlayer electron hopping, a rich three-dimensional phase diagram can be established, including three...
Topological magnets are a new family of quantum materials providing great potential to realize emergent phenomena, such as the anomalous Hall effect and axion-insulator state. Here, we present our discovery that stoichiometric ferromagnet MnBi8Te13 with natural heterostructure MnBi2Te4/(Bi2Te3)3 is an unprecedented "half-magnetic topological insulator," magnetization existing at MnBi2Te4 surface but not opposite terminated by triple Bi2Te3 layers. Our angle-resolved photoemission...