Publications by authors named "Yaobo Huang"

17 Publications

  • Page 1 of 1

A Superlattice-Stabilized Layered CuS Anode for High-Performance Aqueous Zinc-Ion Batteries.

ACS Nano 2021 Oct 29. Epub 2021 Oct 29.

College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.

Rechargeable aqueous zinc ion batteries (AZIBs) are attracting extensive attention owing to environmental friendliness and high safety. However, its practical applications are limited to the poor Coulombic efficiency and stability of a Zn anode. Herein, we demonstrate a periodically stacked CuS-CTAB superlattice, as a competitive conversion-type anode for AZIBs with greatly improved specific capacity, rate performance, and stability. The CuS layers react with Zn to endow high capacity, while CTAB layers serve to stabilize the structure and facilitate Zn diffusion kinetics. Accordingly, CuS-CTAB shows superior rate performance (225.3 mA h g at 0.1 A g with 144.4 mA h g at 10 A g) and a respectable cyclability of 87.6% capacity retention over 3400 cycles at 10 A g. In view of the outstanding electrochemical properties, full batteries constructed with a CuS-CTAB anode and cathode (ZnFeCo(CN) and ZnMnO) are evaluated in coin cells, which demonstrate impressive full-battery performance.
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http://dx.doi.org/10.1021/acsnano.1c05725DOI Listing
October 2021

Proton-Dominated Reversible Aqueous Zinc Batteries with an Ultraflat Long Discharge Plateau.

ACS Nano 2021 Sep 25;15(9):14766-14775. Epub 2021 Aug 25.

Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.

Aqueous zinc batteries (AZBs) are considered promising candidates for large-scale energy storage systems because of their low cost and high safety. However, currently developed AZB cathodes always suffer from the intense charge repulsion of multivalent-ion and complex multiphase electrochemistry, resulting in an insufficient cycling life and impracticable high-sloping discharge profile. Herein, we found that the synthesized ultrathin BiOSe nanosheets can effectively activate stable protons storage in AZBs rather than large zinc ions. This proton-dominated cathode provides an ultraflat discharge plateau (72% capacity proportion) and exhibits long-term cyclability as 90.64% capacity retention after 2300 cycles at 1 A g. Further synchrotron X-ray diffraction, X-ray photoelectronic spectroscopy, and density functional theory confirm the energy storage mechanism regarding the highly reversible proton insertion/extraction process. Benefiting from the proton-dominated fast dynamics, reliable energy supply (>81.5% discharge plateau capacity proportion) is demonstrated at a high rate of up to 10 A g and in the frozen electrolyte below -15 °C. This work provides a potential design of high-performance electrode materials for AZBs.
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http://dx.doi.org/10.1021/acsnano.1c04636DOI Listing
September 2021

Revealing the Heavy Quasiparticles in the Heavy-Fermion Superconductor CeCu_{2}Si_{2}.

Phys Rev Lett 2021 Aug;127(6):067002

Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China.

The superconducting order parameter of the first heavy-fermion superconductor CeCu_{2}Si_{2} is currently under debate. A key ingredient to understand its superconductivity and physical properties is the quasiparticle dispersion and Fermi surface, which remains elusive experimentally. Here, we present measurements from angle-resolved photoemission spectroscopy. Our results emphasize the key role played by the Ce 4f electrons for the low-temperature Fermi surface, highlighting a band-dependent conduction-f electron hybridization. In particular, we find a very heavy quasi-two-dimensional electron band near the bulk X point and moderately heavy three-dimensional hole pockets near the Z point. Comparison with theoretical calculations reveals the strong local correlation in this compound, calling for further theoretical studies. Our results provide the electronic basis to understand the heavy-fermion behavior and superconductivity; implications for the enigmatic superconductivity of this compound are also discussed.
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http://dx.doi.org/10.1103/PhysRevLett.127.067002DOI Listing
August 2021

Dirac cone, flat band and saddle point in kagome magnet YMnSn.

Nat Commun 2021 May 25;12(1):3129. Epub 2021 May 25.

Department of Physics and Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, China.

Kagome-lattices of 3d-transition metals hosting Weyl/Dirac fermions and topological flat bands exhibit non-trivial topological characters and novel quantum phases, such as the anomalous Hall effect and fractional quantum Hall effect. With consideration of spin-orbit coupling and electron correlation, several instabilities could be induced. The typical characters of the electronic structure of a kagome lattice, i.e., the saddle point, Dirac-cone, and flat band, around the Fermi energy (E) remain elusive in magnetic kagome materials. We present the experimental observation of the complete features in ferromagnetic kagome layers of YMnSn helically coupled along the c-axis, by using angle-resolved photoemission spectroscopy and band structure calculations. We demonstrate a Dirac dispersion near E, which is predicted by spin-polarized theoretical calculations, carries an intrinsic Berry curvature and contributes to the anomalous Hall effect in transport measurements. In addition, a flat band and a saddle point with a high density of states near E are observed. These multi-sets of kagome features are of orbital-selective origin and could cause multi-orbital magnetism. The Dirac fermion, flat band and saddle point in the vicinity of E open an opportunity in manipulating the topological properties in magnetic materials.
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http://dx.doi.org/10.1038/s41467-021-23536-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8149840PMC
May 2021

Discovery of [Formula: see text] rotation anomaly in topological crystalline insulator SrPb.

Nat Commun 2021 Apr 6;12(1):2052. Epub 2021 Apr 6.

Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China.

Topological crystalline insulators (TCIs) are insulating electronic states with nontrivial topology protected by crystalline symmetries. Recently, theory has proposed new classes of TCIs protected by rotation symmetries [Formula: see text], which have surface rotation anomaly evading the fermion doubling theorem, i.e., n instead of 2n Dirac cones on the surface preserving the rotation symmetry. Here, we report the first realization of the [Formula: see text] rotation anomaly in a binary compound SrPb. Our first-principles calculations reveal two massless Dirac fermions protected by the combination of time-reversal symmetry [Formula: see text] and [Formula: see text] on the (010) surface. Using angle-resolved photoemission spectroscopy, we identify two Dirac surface states inside the bulk band gap of SrPb, confirming the [Formula: see text] rotation anomaly in the new classes of TCIs. The findings enrich the classification of topological phases, which pave the way for exploring exotic behavior of the new classes of TCIs.
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http://dx.doi.org/10.1038/s41467-021-22350-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024327PMC
April 2021

Formation of Plasmonic Polarons in Highly Electron-Doped Anatase TiO.

Nano Lett 2021 Jan 8;21(1):430-436. Epub 2020 Dec 8.

Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China.

The existence of various quasiparticles of polarons because of electron-boson couplings plays important roles in determining electron transport in titanium dioxide (TiO), which affects a wealth of physical properties from catalysis to interfacial superconductivity. In addition to the well-defined Fröhlich polarons whose electrons are dressed by the phonon clouds, it has been theoretically predicted that electrons can also couple to their own plasmonic oscillations, namely, the plasmonic polarons. Here we experimentally demonstrate the formation of plasmonic polarons in highly doped anatase TiO using angle-resolved photoemission spectroscopy. Our results show that the energy separation of plasmon-loss satellites follows a dependence on √, where is the electron density, manifesting the characteristic of plasmonic polarons. The spectral functions enable to quantitatively evaluate the strengths of electron-plasmon and electron-phonon couplings, respectively, providing an effective approach for characterizing the interplays among different bosonic modes in the complicate many-body interactions.
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http://dx.doi.org/10.1021/acs.nanolett.0c03802DOI Listing
January 2021

Orbital-selective Dirac fermions and extremely flat bands in frustrated kagome-lattice metal CoSn.

Nat Commun 2020 Aug 10;11(1):4002. Epub 2020 Aug 10.

Department of Physics and Beijing Key Laboratory of Opto-Electronic Functional Materials&Micro-Nano Devices, Renmin University of China, Beijing, 100872, China.

Layered kagome-lattice 3d transition metals are emerging as an exciting platform to explore the frustrated lattice geometry and quantum topology. However, the typical kagome electronic bands, characterized by sets of the Dirac-like band capped by a phase-destructive flat band, have not been clearly observed, and their orbital physics are even less well investigated. Here, we present close-to-textbook kagome bands with orbital differentiation physics in CoSn, which can be well described by a minimal tight-binding model with single-orbital hopping in Co kagome lattice. The capping flat bands with bandwidth less than 0.2 eV run through the whole Brillouin zone, especially the bandwidth of the flat band of out-of-plane orbitals is less than 0.02 eV along Γ-M. The energy gap induced by spin-orbit interaction at the Dirac cone of out-of-plane orbitals is much smaller than that of in-plane orbitals, suggesting orbital-selective character of the Dirac fermions.
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http://dx.doi.org/10.1038/s41467-020-17462-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7417585PMC
August 2020

Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd As.

Adv Mater 2020 Apr 24;32(14):e1907565. Epub 2020 Feb 24.

Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.

Parity-time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realization of magnetic topological DSMs remains a major issue in topological material research. Here, combining angle-resolved photoemission spectroscopy with density functional theory calculations, it is ascertained that band inversion induces a topologically nontrivial ground state in EuCd As . As a result, ideal magnetic Dirac fermions with simplest double cone structure near the Fermi level emerge in the antiferromagnetic (AFM) phase. The magnetic order breaks time reversal symmetry, but preserves inversion symmetry. The double degeneracy of the Dirac bands is protected by a combination of inversion, time-reversal, and an additional translation operation. Moreover, the calculations show that a deviation of the magnetic moments from the c-axis leads to the breaking of C3 rotation symmetry, and thus, a small bandgap opens at the Dirac point in the bulk. In this case, the system hosts a novel state containing three different types of topological insulator: axion insulator, AFM topological crystalline insulator (TCI), and higher order topological insulator. The results provide an enlarged platform for the quest of topological Dirac fermions in a magnetic system.
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http://dx.doi.org/10.1002/adma.201907565DOI Listing
April 2020

In Situ Formation of Hierarchical Bismuth Nanodots/Graphene Nanoarchitectures for Ultrahigh-Rate and Durable Potassium-Ion Storage.

Small 2020 Jan 11;16(2):e1905789. Epub 2019 Dec 11.

Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China.

Metallic bismuth (Bi) has been widely explored as remarkable anode material in alkali-ion batteries due to its high gravimetric/volumetric capacity. However, the huge volume expansion up to ≈406% from Bi to full potassiation phase K Bi, inducing the slow kinetics and poor cycling stability, hinders its implementation in potassium-ion batteries (PIBs). Here, facile strategy is developed to synthesize hierarchical bismuth nanodots/graphene (BiND/G) composites with ultrahigh-rate and durable potassium ion storage derived from an in situ spontaneous reduction of sodium bismuthate/graphene composites. The in situ formed ultrafine BiND (≈3 nm) confined in graphene layers can not only effectively accommodate the volume change during the alloying/dealloying process but can also provide high-speed channels for ionic transport to the highly active BiND. The BiND/G electrode provides a superior rate capability of 200 mA h g at 10 A g and an impressive reversible capacity of 213 mA h g at 5 A g after 500 cycles with almost no capacity decay. An operando synchrotron radiation-based X-ray diffraction reveals distinctively sharp multiphase transitions, suggesting its underlying operation mechanisms and superiority in potassium ion storage application.
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http://dx.doi.org/10.1002/smll.201905789DOI Listing
January 2020

Coexistence of Ferromagnetic and Stripe Antiferromagnetic Spin Fluctuations in SrCo_{2}As_{2}.

Phys Rev Lett 2019 Mar;122(11):117204

Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.

We use inelastic neutron scattering to study energy and wave vector dependence of spin fluctuations in SrCo_{2}As_{2}, derived from SrFe_{2-x}Co_{x}As_{2} iron pnictide superconductors. Our data reveal the coexistence of antiferromagnetic (AF) and ferromagnetic (FM) spin fluctuations at wave vectors Q_{AF}=(1,0) and Q_{FM}=(0,0)/(2,0), respectively. By comparing neutron scattering results with those of dynamic mean field theory calculation and angle-resolved photoemission spectroscopy experiments, we conclude that both AF and FM spin fluctuations in SrCo_{2}As_{2} are closely associated with a flatband of the e_{g} orbitals near the Fermi level, different from the t_{2g} orbitals in superconducting SrFe_{2-x}Co_{x}As_{2}. Therefore, Co substitution in SrFe_{2-x}Co_{x}As_{2} induces a t_{2g} to e_{g} orbital switching, and is responsible for FM spin fluctuations detrimental to the singlet pairing superconductivity.
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http://dx.doi.org/10.1103/PhysRevLett.122.117204DOI Listing
March 2019

Observation of unconventional chiral fermions with long Fermi arcs in CoSi.

Nature 2019 03 20;567(7749):496-499. Epub 2019 Mar 20.

Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China.

Chirality-the geometric property of objects that do not coincide with their mirror image-is found in nature, for example, in molecules, crystals, galaxies and life forms. In quantum field theory, the chirality of a massless particle is defined by whether the directions of its spin and motion are parallel or antiparallel. Although massless chiral fermions-Weyl fermions-were predicted 90 years ago, their existence as fundamental particles has not been experimentally confirmed. However, their analogues have been observed as quasiparticles in condensed matter systems. In addition to Weyl fermions, theorists have proposed a number of unconventional (that is, beyond the standard model) chiral fermions in condensed matter systems, but direct experimental evidence of their existence is still lacking. Here, by using angle-resolved photoemission spectroscopy, we reveal two types of unconventional chiral fermion-spin-1 and charge-2 fermions-at the band-crossing points near the Fermi level in CoSi. The projections of these chiral fermions on the (001) surface are connected by giant Fermi arcs traversing the entire surface Brillouin zone. These chiral fermions are enforced at the centre or corner of the bulk Brillouin zone by the crystal symmetries, making CoSi a system with only one pair of chiral nodes with large separation in momentum space and extremely long surface Fermi arcs, in sharp contrast to Weyl semimetals, which have multiple pairs of Weyl nodes with small separation. Our results confirm the existence of unconventional chiral fermions and provide a platform for exploring the physical properties associated with chiral fermions.
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http://dx.doi.org/10.1038/s41586-019-1031-8DOI Listing
March 2019

Author Correction: Large intrinsic anomalous Hall effect in half-metallic ferromagnet CoSnS with magnetic Weyl fermions.

Nat Commun 2018 10 8;9(1):4212. Epub 2018 Oct 8.

Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, 100872, Beijing, China.

The original version of this Article incorrectly omitted an affiliation of Hongming Weng: "Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China"This has been corrected in both the PDF and HTML versions of the Article.
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http://dx.doi.org/10.1038/s41467-018-06643-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175846PMC
October 2018

Large intrinsic anomalous Hall effect in half-metallic ferromagnet CoSnS with magnetic Weyl fermions.

Nat Commun 2018 09 11;9(1):3681. Epub 2018 Sep 11.

Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, 100872, Beijing, China.

The origin of anomalous Hall effect (AHE) in magnetic materials is one of the most intriguing aspects in condensed matter physics and has been a controversial topic for a long time. Recent studies indicate that the intrinsic AHE is closely related to the Berry curvature of occupied electronic states. In a magnetic Weyl semimetal with broken time-reversal symmetry, there are significant contributions to Berry curvature around Weyl nodes, possibly leading to a large intrinsic AHE. Here, we report the quite large AHE in the half-metallic ferromagnet CoSnS single crystal. By systematically mapping out the electronic structure of CoSnS both theoretically and experimentally, we demonstrate that the intrinsic AHE from the Weyl fermions near the Fermi energy is dominating. The intrinsic anomalous Hall conductivity depends linearly on the magnetization and can be reproduced by theoretical simulation, in which the Weyl nodes monotonically move with the constrained magnetic moment on Co atom.
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http://dx.doi.org/10.1038/s41467-018-06088-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6134149PMC
September 2018

Defects controlled hole doping and multivalley transport in SnSe single crystals.

Nat Commun 2018 01 3;9(1):47. Epub 2018 Jan 3.

Department of Physics, Zhejiang University, Hangzhou, 310027, China.

SnSe is a promising thermoelectric material with record-breaking figure of merit. However, to date a comprehensive understanding of the electronic structure and most critically, the self-hole-doping mechanism in SnSe is still absent. Here we report the highly anisotropic electronic structure of SnSe investigated by angle-resolved photoemission spectroscopy, in which a unique pudding-mould-shaped valence band with quasi-linear energy dispersion is revealed. We prove that p-type doping in SnSe is extrinsically controlled by local phase segregation of SnSe microdomains via interfacial charge transferring. The multivalley nature of the pudding-mould band is manifested in quantum transport by crystallographic axis-dependent weak localisation and exotic non-saturating negative magnetoresistance. Strikingly, quantum oscillations also reveal 3D Fermi surface with unusual interlayer coupling strength in p-SnSe, in which individual monolayers are interwoven by peculiar point dislocation defects. Our results suggest that defect engineering may provide versatile routes in improving the thermoelectric performance of the SnSe family.
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http://dx.doi.org/10.1038/s41467-017-02566-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5752673PMC
January 2018

Magnetic moment evolution and spin freezing in doped BaFeAs.

Sci Rep 2017 08 14;7(1):8003. Epub 2017 Aug 14.

Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland.

Fe-K X-ray emission spectroscopy measurements reveal an asymmetric doping dependence of the magnetic moments μ in electron- and hole-doped BaFeAs. At low temperature, μ is nearly constant in hole-doped samples, whereas it decreases upon electron doping. Increasing temperature substantially enhances μ in the hole-doped region, which is naturally explained by the theoretically predicted crossover into a spin-frozen state. Our measurements demonstrate the importance of Hund's-coupling and electronic correlations, especially for hole-doped BaFeAs, and the inadequacy of a fully localized or fully itinerant description of the 122 family of Fe pnictides.
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http://dx.doi.org/10.1038/s41598-017-07286-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5556117PMC
August 2017

Experimental evidence of hourglass fermion in the candidate nonsymmorphic topological insulator KHgSb.

Sci Adv 2017 May 5;3(5):e1602415. Epub 2017 May 5.

Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.

Topological insulators (TIs) host novel states of quantum matter characterized by nontrivial conducting boundary states connecting valence and conduction bulk bands. All TIs discovered experimentally so far rely on either time-reversal or mirror crystal symmorphic symmetry to protect massless Dirac-like boundary states. Several materials were recently proposed to be TIs with nonsymmorphic symmetry, where a glide mirror protects exotic surface fermions with hourglass-shaped dispersion. However, an experimental confirmation of this new fermion is missing. Using angle-resolved photoemission spectroscopy, we provide experimental evidence of hourglass fermions on the (010) surface of crystalline KHgSb, whereas the (001) surface has no boundary state, in agreement with first-principles calculations. Our study will stimulate further research activities of topological properties of nonsymmorphic materials.
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http://dx.doi.org/10.1126/sciadv.1602415DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5419706PMC
May 2017

Ground-state oxygen holes and the metal-insulator transition in the negative charge-transfer rare-earth nickelates.

Nat Commun 2016 10 11;7:13017. Epub 2016 Oct 11.

Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.

The metal-insulator transition and the intriguing physical properties of rare-earth perovskite nickelates have attracted considerable attention in recent years. Nonetheless, a complete understanding of these materials remains elusive. Here we combine X-ray absorption and resonant inelastic X-ray scattering (RIXS) spectroscopies to resolve important aspects of the complex electronic structure of rare-earth nickelates, taking NdNiO thin film as representative example. The unusual coexistence of bound and continuum excitations observed in the RIXS spectra provides strong evidence for abundant oxygen holes in the ground state of these materials. Using cluster calculations and Anderson impurity model interpretation, we show that distinct spectral signatures arise from a Ni 3d configuration along with holes in the oxygen 2p valence band, confirming suggestions that these materials do not obey a conventional positive charge-transfer picture, but instead exhibit a negative charge-transfer energy in line with recent models interpreting the metal-insulator transition in terms of bond disproportionation.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5062575PMC
http://dx.doi.org/10.1038/ncomms13017DOI Listing
October 2016
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