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Liu QM, Wu D, Li ZA, Shi LY, Wang ZX, Zhang SJ, Lin T, Hu TC, Tian HF, Li JQ, Dong T, Wang NL. Photoinduced multistage phase transitions in Ta 2NiSe 5. Nat Commun 2021; 12:2050. [PMID: 33824351 PMCID: PMC8024274 DOI: 10.1038/s41467-021-22345-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/10/2021] [Indexed: 02/01/2023] Open
Abstract
Ultrafast control of material physical properties represents a rapidly developing field in condensed matter physics. Yet, accessing the long-lived photoinduced electronic states is still in its early stages, especially with respect to an insulator to metal phase transition. Here, by combining transport measurement with ultrashort photoexcitation and coherent phonon spectroscopy, we report on photoinduced multistage phase transitions in Ta2NiSe5. Upon excitation by weak pulse intensity, the system is triggered to a short-lived state accompanied by a structural change. Further increasing the excitation intensity beyond a threshold, a photoinduced steady new state is achieved where the resistivity drops by more than four orders at temperature 50 K. This new state is thermally stable up to at least 350 K and exhibits a lattice structure different from any of the thermally accessible equilibrium states. Transmission electron microscopy reveals an in-chain Ta atom displacement in the photoinduced new structure phase. We also found that nano-sheet samples with the thickness less than the optical penetration depth are required for attaining a complete transition.
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Affiliation(s)
- Q M Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - D Wu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China.
| | - Z A Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - L Y Shi
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Z X Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - S J Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - T Lin
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - T C Hu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - H F Tian
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - J Q Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - T Dong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - N L Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, China.
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Dai LS, Tian HF, Hang Y, Wen CW, Huang YH, Wang BF, Hu JW, Xu JP, Deng MJ. 1 H NMR-based metabonomic evaluation of the pesticides camptothecin and matrine against larvae of Spodoptera litura. Pest Manag Sci 2021; 77:208-216. [PMID: 32677739 DOI: 10.1002/ps.6009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/10/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Camptothecin (CPT) and matrine (MAT) have potential as botanical pesticides against several pest species. However, the mechanisms of metabolic and physiological changes in pests induced by CPT and MAT are unknown. In this study, a toxicological test, an NMR-based metabolomic study, an enzymatic test, and an RT quantitative PCR (RT-qPCR) experiment were all conducted to examine the effect of CPT and MAT on Spodoptera litura. RESULTS CPT (0.5-1%) exerted high toxicity against larvae of S. litura and caused growth stagnation and high mortality of larvae. A variety of metabolites were significantly influenced by 0.5% CPT, including several energy-related metabolites such as trehalose, lactate, succinate, citrate, malate, and fumarate. In contrast, MAT showed low toxicity against larvae and induced almost no changes in hemolymph metabolites of S. litura. Enzymatic tests showed that trehalase activity was significantly decreased in larvae after feeding with 0.5% CPT. RT-qPCR showed that the transcription levels of alanine aminotransferase, malate dehydrogenase, and isocitrate dehydrogenase were decreased while lactate dehydrogenase was increased in the 0.5% CPT-treated group. CONCLUSIONS These data indicate that one of the important mechanisms of CPT against S. litura larvae is via the inhibition of trehalose hydrolysis and glycolysis. Our findings also suggest that CPT exhibits a stronger toxicological effect than MAT against S. litura, which provides basic information for the application of CPT in the control of S. litura or other lepidoptera pests.
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Affiliation(s)
- Li-Shang Dai
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Hui-Fei Tian
- School of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yang Hang
- Biotechnology Center of Anhui Agricultural University, Anhui Agricultural University, Hefei, China
| | - Chao-Wei Wen
- School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Ying-Hao Huang
- Renji College, Wenzhou Medical University, Wenzhou, China
| | - Bin-Feng Wang
- School of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Jing-Wei Hu
- Biotechnology Center of Anhui Agricultural University, Anhui Agricultural University, Hefei, China
| | - Jia-Ping Xu
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Ming-Jie Deng
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
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Yang HX, Tian HF, Wang Z, Qin YB, Ma C, Li JQ, Cheng ZY, Yu R, Zhu J. Effect of oxygen stoichiometry in LuFe2O(4-δ) and its microstructure observed by aberration-corrected transmission electron microscopy. J Phys Condens Matter 2012; 24:435901. [PMID: 23032863 DOI: 10.1088/0953-8984/24/43/435901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A series of oxygen deficient LuFe(2)O(4-δ) materials have been prepared under a controlled oxygen partial-pressure atmosphere. Measurements of magnetization reveal that the increase of oxygen deficiencies could evidently depress the ferrimagnetic phase transition temperature (T(N)). In additional to the well-known charge ordering within the (11(-)0) crystal plane, a visible structural modulation with q = (0,1/4.2,7/8) commonly appears on the (100) plane in the oxygen deficient samples. An aberration-corrected transmission electron microscopy study on the oxygen deficient samples demonstrates the presence of oxygen vacancies and local structural distortion. The atomic structural features in correlation with the structural modulation, distortion of the FeO(5) polyhedron and the (001) twinning domains have been also examined.
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Affiliation(s)
- H X Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Yang HX, Tian HF, Song YJ, Qin YB, Zhao YG, Ma C, Li JQ. Polar nanodomains and giant converse magnetoelectric effect in charge-ordered Fe2OBO3. Phys Rev Lett 2011; 106:016406. [PMID: 21231761 DOI: 10.1103/physrevlett.106.016406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Indexed: 05/30/2023]
Abstract
The magnetoelectric coupling and polar nanodomains in the charge-ordered Fe2OBO3 have been extensively studied from room temperature down to 100 K. In situ TEM investigations demonstrate that the charge-ordering transition characterized by an incommensurate modulation could evidently result in remarkable polar nanodomains at low temperatures. This kind of nanodomain could play a critical role in triggering a high dielectric constant and notable dielectric dispersion as observed in Fe2OBO3. Moreover, measurements of the magnetoelectric coupling under electrical field demonstrate the existence of giant electrically induced changes in magnetization around the magnetic transition.
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Affiliation(s)
- H X Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Shi HL, Yang HX, Tian HF, Lu JB, Wang ZW, Qin YB, Song YJ, Li JQ. Structural properties and superconductivity of SrFe(2)As(2 - x)P(x) (0.0 ≤ x ≤ 1.0) and CaFe(2)As(2 - y)P(y) (0.0 ≤ y ≤ 0.3). J Phys Condens Matter 2010; 22:125702. [PMID: 21389495 DOI: 10.1088/0953-8984/22/12/125702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The SrFe(2)As(2 - x)P(x) (0.0 ≤ x ≤ 1.0) and CaFe(2)As(2 - y)P(y) (0.0 ≤ y ≤ 0.3) materials were prepared by a solid-state reaction method. X-ray diffraction measurements indicate that the single-phase samples can be successfully obtained for SrFe(2)As(2 - x)P(x) (0.0 ≤ x ≤ 0.8) and CaFe(2)As(2 - y)P(y) (0.0 ≤ y ≤ 0.3). Visible contraction of the lattice parameters is determined due to the relatively smaller radius of P ions in comparison with that of As. The spin-density-wave (SDW) instability associated with the tetragonal to orthorhombic phase transition is suppressed noticeably in both systems following the increase in P content. The highest superconducting transitions are observed at about 27 K in SrFe(2)As(1.3)P(0.7) and at about 13 K in CaFe(2)As(1.925)P(0.075), respectively. Structural analysis suggests that lattice contraction could notably affect the superconductivity in these materials.
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Affiliation(s)
- H L Shi
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Qin YB, Yang HX, Zhang Y, Tian HF, Ma C, Zhao YG, Walton RI, Li JQ. The effect of Mg doping on the structural and physical properties of LuFe(2)O(4) and Lu(2)Fe(3)O(7). J Phys Condens Matter 2009; 21:015401. [PMID: 21817220 DOI: 10.1088/0953-8984/21/1/015401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The structural and physical properties of the recently discovered electronic ferroelectric materials LuFe(2)O(4) and Lu(2)Fe(3)O(7) have been investigated for Mg substitution of Fe. X-ray diffraction data demonstrate that the lattice parameters in both systems change progressively with increasing Mg content, with a smaller unit cell volume on replacing Fe(2+) by Mg(2+). X-ray absorption near-edge spectroscopy experiments at the Fe K-edge show that the average Fe oxidation state is slightly increased along with Mg doping in Lu(2)Fe(3)O(7) materials, consistent with isomorphous replacement of Fe(2+) by Mg(2+). Measurements of dielectric properties demonstrate that Mg doping could have an effect on the electron hopping energy between Fe(2+) and Fe(3+) ions. Transmission electron microscopy and magnetization analysis reveal that Mg doping in LuFe(2)O(4) has a much greater influence than in Lu(2)Fe(3)O(7) on both the charge ordering and the low-temperature magnetic properties.
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Affiliation(s)
- Y B Qin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Yang HX, Zhu BP, Zeng LJ, Tian HF, Ma C, Shi J, Li JQ. Structural modulation in the orbitally induced Peierls state of MgTi(2)O(4). J Phys Condens Matter 2008; 20:275230. [PMID: 21694391 DOI: 10.1088/0953-8984/20/27/275230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The structural properties associated with the orbitally induced Peierls transition in MgTi(2)O(4) are characterized by in situ cooling TEM observations. A distinctive structural modulation with the wavevector of q(1) = 1/4 (0, 0, 4) has been well demonstrated below a critical temperature of about 260 K for MgTi(2)O(4). Systematic analysis demonstrates that this structural modulation can be well explained by an orbital order existing in the low-temperature insulating phase. It is also noted that the nonstoichiometric feature commonly appearing in the present system could yield visible changes in both physical and structural properties. A low-temperature study of the microstructure of Mg[Ti(1.9)Mg(0.1)]O(4) reveals that a little substitution of Mg(2+) for Ti(3+) ions on the octahedral sites can disrupt the long-range order of the t(2g) orbitals, resulting in complex tweed structures in the superstructure phase.
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Affiliation(s)
- H X Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China
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Ma C, Xiao RJ, Geng HX, Yang HX, Tian HF, Che GC, Li JQ. Investigation of hole states near the Fermi level in Nb(1-)(x)Mg(x)B(2) by electron energy-loss spectroscopy and first-principles calculations. Ultramicroscopy 2007; 108:320-6. [PMID: 17560031 DOI: 10.1016/j.ultramic.2007.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 04/04/2007] [Accepted: 05/01/2007] [Indexed: 10/23/2022]
Abstract
The fine structures of the electron energy-loss spectra (EELS) for the B-K edge have been examined in NbB(2) and superconducting Nb(0.75)Mg(0.25)B(2). The experimental results are analyzed based on the calculations of density functional theory (DFT) using the Wien2k code. The results of the EELS spectra and the angular decomposition of the density of states (DOS) reveal that both the B p(z) and B p(x)+p(y) states in NbB(2) have large weights at the Fermi energy due to intersheet covalent bonding with notable hybridization between the Nb 4d and B 2p states. This kind of hybridization also results in different core-hole behaviors for the B-K edge in two orthogonal crystallographic orientations. The best fit between experimental and theoretical data is achieved with consideration of the core-hole effect of the B 1s states, in particular for the q perpendicular c spectra. Analysis of the electronic structure of the Nb(1-)(x)Mg(x)B(2) superconductors suggests that confinement of the intersheet covalent bonding is likely to be favorable for the improvement of superconductivity in this kind of materials.
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Affiliation(s)
- C Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
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Abstract
The structural features of the charge ordering states in LuFe(2)O(4) are characterized by in situ cooling transmission electron microscopy observations from 300 K down to 20 K. Two distinctive structural modulations, a major q1=(1/3,1/3,2) and a weak q2 = q1/10+(0,0,3/2), have been well determined at the temperature of approximately 20 K. Systematic analysis demonstrates that the charges at low temperatures are well crystallized in a charge-stripe phase, in which the charge-density wave behavior in a nonsinusoidal fashion results in elemental electric dipoles for ferroelectricity. It is also noted that the charge ordering and ferroelectric domains often change markedly with lowering temperatures and yield a rich variety of structural phenomena.
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Affiliation(s)
- Y Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China
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Li JQ, Chen HY, Zhang HR, Yu HC, Shi YG, Liu LB, Tian HF, Zhu Y, Tranquada JM. Structural properties and charge ordered states in RMnO3 (R=La, Pr, Nd, Ca, Sr) and (La, Sr)2NiO4. Micron 2004; 35:419-24. [PMID: 15120125 DOI: 10.1016/j.micron.2004.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2003] [Accepted: 01/19/2004] [Indexed: 11/28/2022]
Abstract
Structural distortions arising from the condensations of two essential kinds of phonon modes: the triply degenerate rotational modes (phix, phiy, phiz) of MnO(6) and the doubly degenerate Jahn-Teller active modes (Q1, Q2) have been systematically investigated in the perovskite manganites. Microstructural features associated with certain types of distortions have been observed by transmission electron microscopy (TEM). In RMnO(3) and La(Sr)(2)NiO(4), we characterize the local structure, charge ordered states and orbital ordering by means of low-temperature TEM. We present direct evidence that the stripe modulation in La(Sr)(2)NiO(4) is indeed one-dimensional within each NiO(2) plane. Several typical kinds of defect structures, including antiphase boundaries and the 90 degrees -twin domains, appear commonly in the charge-ordered states.
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Affiliation(s)
- J Q Li
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
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