A5100711503- Topological Materials and Phenomena
- Graphene research and applications
- Quantum and electron transport phenomena
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- 2D Materials and Applications
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Nonlinear Partial Differential Equations
- Atomic and Subatomic Physics Research
- Electronic and Structural Properties of Oxides
- Quantum optics and atomic interactions
- Multiferroics and related materials
- Advanced Mathematical Physics Problems
- Semiconductor Quantum Structures and Devices
- Cold Atom Physics and Bose-Einstein Condensates
- Heusler alloys: electronic and magnetic properties
- Advanced Mathematical Modeling in Engineering
- Iron-based superconductors research
- Advancements in Semiconductor Devices and Circuit Design
- Characterization and Applications of Magnetic Nanoparticles
- Nonlinear Differential Equations Analysis
- Computational Physics and Python Applications
- Quantum chaos and dynamical systems
- Stochastic processes and financial applications
Chinese Academy of Sciences
2015-2024
University of Chinese Academy of Sciences
2016-2024
Institute of Physics
2015-2024
CCCC Highway Consultants (China)
2024
Fujian Normal University
2005-2023
Songshan Lake Materials Laboratory
2019-2023
Nicolaus Copernicus University
2023
Czech Academy of Sciences, Institute of Physics
2016-2022
Beijing University of Technology
2022
National Center for Nanoscience and Technology
2016-2020
The dispersive properties of the atomic transition in rubidium ${D}_{2}$ line ($5{S}_{\frac{1}{2}}\ensuremath{-}5{P}_{\frac{3}{2}}$) at 780.0 nm are measured with a Mach-Zehnder interferometer when an additional coupling field 775.8 is applied to upper ($5{P}_{\frac{3}{2}}\ensuremath{-}5{D}_{\frac{5}{2}}$). This ladder-type system observed exhibit electromagnetically induced transparency together rapidly varying refractive index. A reduction group velocity for probe beam...
We develop a theory of electromagnetically induced transparency in three-level, ladder-type Doppler-broadened medium, paying special attention to the case where coupling and probe beams are counterpropagating have similar frequencies, so as reduce total Doppler width two-photon process. The is easily generalized deal with \ensuremath{\Lambda} configuration, ideal arrangement involves two copropagating beams. discuss different possible regimes, depending on relative importance various...
We report that Bi₂Se₃ thin films can be epitaxially grown on SrTiO₃ substrates, which allow for very large tunablity in carrier density with a back gate. The observed low field magnetoconductivity due to weak antilocalization (WAL) has gate-voltage dependence unless the electron is reduced values. Such transition WAL correlated unusual changes longitudinal and Hall resistivities. Our results suggest much suppressed bulk conductivity at negative gate voltages possible role of surface states phenomena.
A strong coupling standing wave, interacting with three-level \ensuremath{\Lambda}-type (or ladder-type) atoms, can diffract a weak probe field (propagating along direction normal to the wave) into high-order diffractions, phenomenon which we name electromagnetically induced grating (EIG). We develop in this work theory for studying EIG homogeneously broadened medium consisting of atoms. show that by taking advantage absorption and dispersion properties transparency one create an atomic...
We report an experimental observation of the enhancement nondegenerate four-wave mixing (NDFWM) based on electromagnetically induced transparency (EIT) in a lambda-type three-level system rubidium atoms. measured both linear susceptibility Im χD(1) (absorption) and third-order nonlinear coefficient χD(3) separately for NDFWM process at low atomic density. found that, owing to EIT effect, absorption term is greatly reduced, while generation resonantly enhanced, permitting us observe...
Abstract The growth of high quality, gate‐tunable topological insulator Bi 2 Se 3 thin films on SrTiO substrates by molecular beam epitaxy is reported in this paper. optimized substrate preparation procedures are critical for obtaining undoped with sufficiently low carrier densities while maintaining the strong dielectric strength substrates. large tunability chemical potential manifested greatly enhanced longitudinal resistivity and reversal sign Hall at negative back‐gate voltages. These...
Three-dimensional topological insulators are a new class of quantum matter which has interesting connections to nearly all main branches condensed physics. In this article, we briefly review the advances in field effect control chemical potential three-dimensional insulators. It is essential observation many exotic phenomena predicted emerge from and their hybrid structures with other materials. We also describe various methods for probing surface state transport. Some challenges...
Anderson localization, the absence of diffusive transport in disordered systems, has been manifested as hopping numerous electronic whereas recently discovered topological insulators it not directly observed. Here, we report experimental demonstration a crossover from weak antilocalization regime to variable range localization with ultrathin $({\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Sb}}_{x}{)}_{2}{\mathrm{Te}}_{3}$ films. As disorder becomes stronger, negative magnetoconductivity due is...
Atomically smooth, single crystalline (Bi1−xSbx)2Te3 films have been grown on SrTiO3(111) substrates by molecular beam epitaxy. A full range of Sb-Bi compositions studied in order to obtain the lowest possible bulk conductivity. For samples with optimized Sb (x=0.5±0.1), carrier type can be tuned from n-type p-type across whole thickness help a back-gate. Linear magnetoresistance has observed at gate voltages close maximum longitudinal resistance (Bi0.5Sb0.5)2Te3 sample. These highly tunable...
We report the observation of colossal positive magnetoresistance (MR) in single crystalline, high mobility TaAs2 semimetal. The excellent fit MR by a quadratic function magnetic field B over wide temperature range (T = 2–300 K) suggests semiclassical nature MR. measurements Hall effect and Shubnikov-de Haas oscillations, as well band structure calculations, suggest that giant originates from nearly perfectly compensated electrons holes TaAs2. can even exceed 1 200 000% at 9 T 2 K, which is...
We report that the finite thickness of three-dimensional topological insulator (TI) thin films produces an observable magnetoresistance (MR) in phase coherent transport parallel magnetic fields. The MR data Bi${}_{2}$Se${}_{3}$ and (Bi${}_{1\ensuremath{-}x}$Sb${}_{x}$)${}_{2}$Te${}_{3}$ are compared with existing theoretical models field magnetotransport. conclude TI bring into a unique regime which coupling surface states to bulk opposite surfaces is indispensable for understanding observed...
The evolution of the quantum anomalous Hall effect with thickness Cr-doped (Bi,Sb)2 Te3 magnetic topological insulator films is studied, revealing how caused by interplay surface states, band-bending, and ferromagnetic exchange energy. Homogeneity in ferromagnetism found to be key high-temperature material.
Various mechanisms of electrical generation spin polarization in nonmagnetic materials have been a subject broad interest for their underlying physics and device potential spintronics. One such scheme is chirality-induced selectivity (CISS), with which structural chirality leads to different electric conductivities electrons opposite spins. The resulting effect filtering has reported number chiral molecules assembled on surfaces. However, the microscopic origin transport remain...
Single crystals of $\mathrm{EuMnS}{\mathrm{b}}_{2}$ were successfully grown and their structural electronic properties investigated systematically. The material crystallizes in an orthorhombic-layered structure (space group: Pnma, No. 62) comprising a periodic sequence -MnSb/Eu/Sb/Eu/- layers ($\ensuremath{\sim}1\phantom{\rule{0.16em}{0ex}}\mathrm{nm}$ thickness), massless fermions are expected to emerge the Sb layer, by analogy candidate Dirac materials $\mathrm{EuMnB}{\mathrm{i}}_{2}$...
High quality HgCr2Se4 single crystals have been investigated by magnetization, electron transport, and Andreev reflection spectroscopy. In the ferromagnetic ground state, saturation magnetic moment of each unit cell corresponds to an integer number spins (3 μB/Cr3+), Hall effect measurements suggest n-type charge carriers. Spin polarizations as high 97% were obtained from fits differential conductance spectra HgCr2Se4/Pb junctions with modified Blonder-Tinkham-Klapwijk theory. The...
The anomalous Hall (AH) effect measurement has emerged as a powerful tool to gain deep insights into magnetic materials, such ferromagnetic metals, semiconductors, and topological insulators (TIs). In Mn-doped Bi2Se3, however, the AH never been reported despite lot of previous studies. Here we report observation in (Bi,Mn)2Se3 thin films show that sign resistances changes from positive negative Mn concentration is increased. are found coexist crossover regime. Such two-component reversal can...
We review theoretical and experimental highlights in transport two-dimensional materials focussing on key developments over the last five years. Topological insulators are finding applications magnetic devices, while Hall doped samples general issue of topological protection remain controversial. In transition metal dichalcogenides valley-dependent electrical optical phenomena continue to stimulate state-of-the-art experiments. Weyl semimetals properties Fermi arcs being actively...
We report on low-temperature electron transport properties of MnSb 2 Te 4 , a candidate ferrimagnetic Weyl semimetal. Long-range magnetic order is manifested as nearly square-shaped hysteresis loop in the anomalous Hall resistance, well sharp jumps magnetoresistance. At temperatures below K, ln T-type upturn appears temperature dependence longitudinal which can be attributed to electron-electron interaction (EEI), since weak localization excluded by Although resistance exhibits similar same...
Research interests in recent years have expanded into quantum materials that display novel magnetism incorporating strong correlations, topological effects, and dimensional crossovers. Fe 3 GeTe 2 represents such a two-dimensional van der Waals platform exhibiting itinerant ferromagnetism with many intriguing properties. Up to date, most electronic transport studies on been limited its anomalous Hall responses while the longitudinal counterpart (such as magnetoresistance) remains largely...
Abstract Study of the dephasing in electronic systems is not only important for probing nature their ground states, but also crucial to harnessing quantum coherence information processing. In contrast well-studied conventional metals and semiconductors, it remains unclear which mechanism mainly responsible electron three-dimensional topological insulators (TIs). Here, we report on using weak antilocalization effect measure rates highly tunable (Bi,Sb) 2 Te 3 thin films. As transport varied...
In three-dimensional topological insulators (TIs), the nontrivial topology in their electronic bands casts a gapless state on solid surfaces, using which dissipationless TI edge devices based quantum anomalous Hall (QAH) effect and (QH) have been demonstrated. Practical present pair of parallel-transport surface states (TSSs) top bottom surfaces. However, due to no-go theorem, two TSSs always appear as are expected quantize synchronously. Quantized transport separate Dirac channel is still...
We report that thin films of a prototype topological insulator, Bi2Se3, can be epitaxially grown onto the (0001) surface BaFe12O19 (BaM), magnetic insulator with high Curie temperature and large perpendicular anisotropy. In Bi2Se3 on non-magnetic substrates, classic weak antilocalization (WAL) is manifested as cusp-shaped positive magnetoresistance (MR) in fields parabola-shaped MR parallel fields, whereas Bi2Se3/BaM heterostructures low field parabola-shaped, which negative fields. The...
High-sensitivity magnetometry over a wide temperature range has been achieved using submicron GaAs/GaAlAs Hall gradiometry. The sensitivity and versatility of the technique was demonstrated by successful measurement magnetization switching single Fe nanoparticle with m∼5×105 μB (∼5×10−15 emu) at temperatures as high 75 K.