npj Quantum Materials
·
2020
·Vol. 5
·期 1
·1-8
·
IF 6.562
Cheng Erjian,Xia Wei,Shi Xianbiao,Yu Zhenhai,Wang Lin,Yan Limin,Peets Darren C.,Zhu Chuchu,Su Hao,Zhang Yong,Dai Dongzhe,Wang Xia,Zou Zhiqiang,Yu Na,Kou Xufeng,Yang Wenge,Zhao Weiwei,Guo Yanfeng,Li Shiyan
Topological nodal-line semimetals (TNLSMs) are materials whose conduction and valence bands cross each other, meeting a topologically protected closed loop rather than discrete points in the Brillouin zone (BZ). The anticipated properties for TNLSMs, include drumhead-like nearly flat surface states, unique Landau energy levels, special collective modes, long-range Coulomb interactions, or the possibility of realizing high-temperature superconductivity. Recently, SrAs 3 has been theoretically proposed and then experimentally confirmed to be a TNLSM. Here, we report high-pressure experiments on SrAs 3 , identifying a Lifshitz transition below 1 GPa and a superconducting transition accompanied by a structural phase transition above 20 GPa. A topological crystalline insulator (TCI) state is revealed by means of density functional theory (DFT) calculations on the emergent high-pressure phase. As the counterpart of topological insulators, TCIs possess metallic boundary states protected by crystal symmetry, rather than time reversal. In consideration of topological surface states (TSSs) and helical spin texture observed in the high-pressure state of SrAs 3 , the superconducting state may be induced in the surface states, and is most likely topologically nontrivial, making pressurized SrAs 3 a strong candidate for topological superconductor.
研究领域:
凝聚态物理学
·
材料科学
✓ 已验证
DOI
高影响因子
ACS Photonics
·
2025
·
IF 6.7
Yanshu Shi,Jianhua Zhu,Xuekun Wang,Yiqian Wang,Qinghao Song,Lei Chen,Yumin Song,Wei Wu,Tingting Guo
Topological Photonics, exploring the topologically nontrivial states in photonics, is a fast-progressing research topic. Topological flat bands, fascinating features in topological photonics, have attracted much attention recently. Metal-phthalocyanine (MPc) molecular semiconductors are formed by molecular chains, offering a great platform to study topological states in low dimension. Previous work shows that the MPc molecular chain could be used to realize one-dimensional topological excitons based on the two-level systems. Therein, the topological flat band is a key feature in this type of topological excitons. Here, we have synthesized tin-phthalocyanine (SnPc) nanosheets. The ultraviolet–visible (UV–vis) and photoelectric experiments on these SnPc nanosheets are performed to characterize the one-dimensional topological flat bands. We demonstrate the strong evidence that the two photocurrent peaks at the wavelengths of 455 and 850 nm could originate from the topological flat bands within the B- and Q-spectral regions, respectively, according to our excitonic model. In addition, the photocurrent is improved by up to two orders using the nanosheets compared to the raw materials. Moreover, the previous excitonic model consisting of two-level systems is further generalized to incorporate both the B- and Q-bands by using three-level systems, interpreting the UV–vis spectra and the photocurrent peaks properly. The combination of our experimental and theoretical research shows that the stable and high broadband photoelectric performance of the SnPc nanosheets not only provides a new material platform for the organic photodetectors but also opens up a new research avenue for the observation of the topological flat band using molecular materials.
研究领域:
拓扑光子学
·
凝聚态物理
·
材料科学
·
光电子学
·
分子半导体
✓ 已验证
DOI
高影响因子
Matter
·
2020
·
IF 0
Cheng Chen,Aiji Liang,Shuai Liu,Simin Nie,Junwei Huang,Meixiao Wang,Yiwei Li,Ding Pei,Haifeng Yang,Huijun Zheng,Yong Zhang,Donghui Lu,Makoto Hashimoto,Alexei Barinov,Chris Jozwiak,Aaron Bostwick,Eli Rotenberg,Xufeng Kou,Lexian Yang,Yanfeng Guo,Zhijun Wang,Hongtao Yuan,Zhongkai Liu,Yulin Chen
Topological superconductors (TSCs), with the capability to host Majorana bound states that can lead to non-Abelian statistics and application in quantum computation, have been one of the most intensively studied topics in condensed matter physics recently. To date, only a few compounds have been proposed as candidates of intrinsic TSCs, such as doped topological insulator Cu x Bi 2 Se 3 and iron-based superconductor FeTe 0.55 Se 0.45 . Here, by carrying out synchrotron- and laser-based angle-resolved photoemission spectroscopy, we systematically investigated the electronic structure of a quasi-one-dimensional superconductor TaSe 3 and identified the non-trivial topological surface states. In addition, our scanning tunneling microscopy study revealed a clean cleaved surface with a persistent superconducting gap, proving it suitable for further investigation of potential Majorana modes. These results prove TaSe 3 as a stoichiometric TSC candidate that is stable and exfoliable and therefore a promising platform for the study of rich novel phenomena and application potentials.
研究领域:
凝聚态物理
·
拓扑量子材料
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超导电子学
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表面科学
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量子计算
✓ 已验证
DOI
Nanomaterials
·
2019
·Vol. 9
·期 8
·1062
·
IF 4.034
Yi Chu,Yingjie Xing,Hongqi Xu
SmB6nanowires, as a prototype of nanostructured topological Kondo insulator, have shown rich novel physical phenomena relating to their surface. Catalyst-assisted chemical vapor deposition (CVD) is a common approach to prepare SmB6nanowires and Ni is the most popular catalyst used to initiate the growth of SmB6nanowires. Here, we study the effect of growth mechanism on the surface of SmB6nanowires synthesized by CVD. Two types of SmB6nanowires are obtained when using Ni as the catalyst. In addition to pure SmB6nanowires without Ni impurity, a small amount of Ni is detected on the surface of some SmB6nanowires by element analysis with transmission electron microscopy. In order to eliminate the possible distribution of Ni on nanowire surface, we synthesize single crystalline SmB6nanowires by CVD without using catalyst. The difference between catalyst-assisted and catalyst-free growth mechanism is discussed.Keywords:nanowires;synthesis;CVD;topological insulators;growth mechanism
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MOLECULES
·
2019
·Vol. 24
·期 7
·1311
·
IF 3.06
Ming-Jie Chu,Wei Wang,Zi-Li Ren,Hao Liu,Xiang Cheng,Kai Mo,Li Wang,Feng Tang,Xian-Hai Lv
To develop new antibacterial agents, a series of novel triazole-containing pyrazole ester derivatives were designed and synthesized and their biological activities were evaluated as potential topoisomerase II inhibitors. Compound4dexhibited the most potent antibacterial activity with Minimum inhibitory concentration (MIC) alues of 4 µg/mL, 2 µg/mL, 4 µg/mL, and 0.5 µg/mL againstStaphylococcus aureus,Listeria monocytogenes,Escherichia coli, andSalmonella gallinarum, respectively. The in vivo enzyme inhibition assay4ddisplayed the most potent topoisomerase II (IC50= 13.5 µg/mL) and topoisomerase IV (IC50= 24.2 µg/mL) inhibitory activity. Molecular docking was performed to position compound4dinto the topoisomerase II active site to determine the probable binding conformation. In summary, compound4dmay serve as potential topoisomerase II inhibitor.Keywords:pyrazole;triazole;ester;antibacterial;topoisomerase II inhibitor
研究领域:
药理学
·
微生物学
·
药物化学
✓ 已验证
DOI
PubMed
高影响因子
Microstructures
·
2024
·Vol. 4
·期 1
·N
·
IF 0
Yanmei Ma,Hongbo Wang,Ruihong Li,Han Liu,Jian Zhang,Xianyu Wang,Qiang Jing,Xu Wang,Wenping Dong,Jinman Chen,Bingze Wu,Yonghao Han,Dan Zhou,Chunxiao Gao
Owing to their unique compositional and structural characteristics, layered van der Waals solids in binary and ternary chalcogenide families provide a fertile testbed for exploring novel exotic structures and states, e.g., topological insulators and superconductors. Herein, a comprehensive study on the structural variations and correlated electrical transport behavior of SnSb2Te4, a ternary member, has been carried out considering elevated pressures. Under 45.6 GPa, three distinct structural phase transitions have been observed, with strong evidence from the variations of high-pressure X-ray diffraction patterns. The onsets of phase II (monoclinic, C2/m) at 6.3 GPa, phase III (monoclinic, C2/c) at 15.5 GPa, and phase IV (body-centered cubic with substitutional disorder, Im-3m) at 17.2 GPa have been observed owing to the emergence of new diffractions. Based on electrical measurements at low temperature and high pressure conditions, two pressure-induced superconducting states have been distinguished in SnSb2Te4. The first state occurs in the range of 12.3-17.1 GPa. The positive pressure dependence on Tc indicates that the aforementioned state is related to the monoclinic C2/m phase. At > 17.1 GPa, the second superconducting state emerges, with the negative pressure dependence on Tc. It relates to the body-centered cubic solid solution phase, which is characteristic of a substitutional disordered crystal structure. The discovery that the pressure-induced superconductivity in SnSb2Te4 is affected by structural phase transitions under pressure may help understand the universal relationship between the ambient condition topological insulating state and derived superconductivity. Ab initio theoretical calculations reveal that an electronic topological transition takes place at approximately 2.0 GPa, which is featured by the obvious changes in the distribution of electronic density of states near the Fermi level.
研究领域:
凝聚态物理
·
材料科学
✓ 已验证
DOI
Nature Communications
·
2021
·Vol. 12
·期 1
·1-9
·
IF 14.919
Cheng Erjian,Xia Wei,Shi Xianbiao,Fang Hongwei,Wang Chengwei,Xi Chuanying,Xu Shaowen,Peets Darren C.,Wang Linshu,Su Hao,Pi Li,Ren Wei,Wang Xia,Yu Na,Chen Yulin,Zhao Weiwei,Liu Zhongkai,Guo Yanfeng,Li Shiyan
The nature of the interaction between magnetism and topology in magnetic topological semimetals remains mysterious, but may be expected to lead to a variety of novel physics. We systematically studied the magnetic semimetal EuAs 3 , demonstrating a magnetism-induced topological transition from a topological nodal-line semimetal in the paramagnetic or the spin-polarized state to a topological massive Dirac metal in the antiferromagnetic ground state at low temperature. The topological nature in the antiferromagnetic state and the spin-polarized state has been verified by electrical transport measurements. An unsaturated and extremely large magnetoresistance of ~2 × 10 5 % at 1.8 K and 28.3 T is observed. In the paramagnetic states, the topological nodal-line structure at the Y point is proven by angle-resolved photoemission spectroscopy. Moreover, a temperature-induced Lifshitz transition accompanied by the emergence of a new band below 3 K is revealed. These results indicate that magnetic EuAs 3 provides a rich platform to explore exotic physics arising from the interaction of magnetism with topology.
研究领域:
凝聚态物理
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry B
·
2021
·Vol. 9
·期 48
·9863-9873
·
IF 6.331
Qing Bo Tong,Cong Du,Zhou Wei,Miao Du,Zi Liang Wu,Qiang Zheng
Revealing the relationship between network topologies and mechanical properties of hydrogels is fundamental yet challenging in the design of tough soft materials. Here, we report a series of hydrogels using N-isopropyl acrylamide (NIPAm) and acrylic acid (AAc) as the basic units to form a single network of the copolymer, a semi-interpenetrated network of two homopolymers, and a grafted network with homopolymer chains anchored on another homopolymer network, to investigate the influence of network architectures on the mechanical properties and thermal responses of the gels. We found that the properties of the gels are also significantly influenced by the formation of hydrogen bonds between poly(N-isopropyl acrylamide) (PNIPAm) and poly(acrylic acid) (PAAc) segments. The gels with the single network of poly(NIPAm-co-AAc) are mechanically weak due to the low efficiency for forming robust hydrogen bonds, while micro-segregated domains are formed in the hydrogels with a semi-interpenetrated network structure due to the formation of inter-chain hydrogen bonds that favors energy dissipation and toughening of the gels. On the other hand, dense hydrogen bonds form between the grafted PNIPAm chains and the PAAc network, resulting in nano-segregated domains and excellent mechanical properties of the gels. The hydrogels with the grafted network structure exhibit a more repeatable response to temperature than those with the semi-interpenetrated network structure due to the relatively stable hydrogen-bond network. The comparison of the mechanical properties and thermal stability of the hydrogels with the same composition but different topological networks should be informative for engineering hydrogel properties or functions by tailoring the network structures.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Ruihong Li,Guangtao Liu,Qiang Jing,Xianyu Wang,Hongbo Wang,Jian Zhang,Yanmei Ma
The materials with topological phases have been a flexible platform for the realization of novel types of quantum matter due to their unique topology protected electron states. Herein, we report a comprehensive structural and electrical transport investigations on a topological insulator, SnBi 2 Te 4 , under high pressures by using diamond anvil cell techniques. Through in situ high pressure synchrotron x-ray diffraction studies, two structural phase transformations have been revealed. The powdered samples of SnBi 2 Te 4 transform from the initial layered quasi-two-dimensional structure (phase I) to a monoclinic C2/m structure (phase II) at about 7.14 GPa, and eventually develop into a site-disordered body centered cubic structure (phase III) at pressures above 18.9 GPa. Modifications of the electronic band structure have been discovered by the in situ high-pressure electrical measurements at low temperatures. It is noteworthy that three distinct pressure induced superconducting states have been observed, one in phase II and two in phase III. In each of the pressure induced superconducting states, the critical temperature Tc decreases with pressure. The maximum value of Tc is obtained in the third superconducting state emerging at the highest pressure range, which is 8.9 K at 22.3 GPa. A deep understanding of the relationship between the pressure induced structure-dependent superconducting states and the ambient-pressure topologically insulating state of SnBi 2 Te 4 may shed light on the universal physical nature that creates topologically insulating or superconducting states.
研究领域:
凝聚态物理
·
材料科学
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2013
·
IF 2.072
De-Kun Ma,Shu-Mei Zhou,Xia Hu,Qiao-Rong Jiang,Shao-Ming Huang
We present here a facile one-pot surfactant-free solvothermal route to synthesize hierarchical BiOI microspheres assembled from nanosheets at 120 °C for 16 h. The as-synthesized BiOI microspheres could be topochemically converted into hollow hierarchical Bi 2 WO 6 ones built by nanoplates for the first time under hydrothermal condition because of the analogies of crystal structures. The transformation process of hierarchical BiOI microspheres to hollow Bi 2 WO 6 ones was surveyed through XRD analyses and FE-SEM observations of the intermediates at different reaction stages. Rhodamine B (RhB) was selected as pollutant model and visible-light-driven photocatalytic activities of hierarchical BiOI and Bi 2 WO 6 microspheres under the same measurement conditions were comparatively studied. As a result, the photocatalytic activities of BiOI obviously outshone Bi 2 WO 6 . The present study not only develops a new method for fabricating hierarchical architectures but also provides some useful information on relative visible-light-responding photocatalytic activity of hierarchical BiOI and Bi 2 WO 6 microspheres.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Science China-Chemistry
·
2025
·
IF 9.7
Sun Haofeng,Wang Minghao,Li Wenjie,Liu Yang,Sun Xinyu,Wang Wenjie,Guo Yuqiao,Xie Yi,Wu Changzheng
Considerable progress has been made in synthesizing two-dimensional (2D) materials by exfoliating layered solids. However, for tremendous non-layered inorganic materials, especially magnet solids, usually with closely packed bulk phases by strong chemical bonds, it is challenging to obtain their high-quality 2D sheets. Herein, we highlighted a new structure of free-standing ferromagnetic nanosheets featuring (111) facets. For magnet, Fe 3 O 4 , its inversed spinel crystalline has limited abilities to exfoliate into 2D forms and rarely exists as free-standing nanosheets owing to aggregation induced by magnetic force. We realized a breakthrough in achieving free-standing ferromagnetic nanosheets with dramatically surpassing size limitations via topotactic conversion from layered counterparts. Our Fe 3 O 4 nanosheets exhibited a maximum width of 60 µm while only ∼4 nm thick, prominently exposing (111) facets. 2D Fe 3 O 4 behaved anisotropic magnetism, which displayed a 4.6 emu g −1 moment ( H =500 Oe) in the (111) plane but 2.1 emu g −1 out of the (111) plane, indicating a (111) in-plane easy axis. We anticipated our topotactic conversion strategy would inspire the creation of 2D non-layered materials and enrich the 2D materials family.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Yiqiu Shi,Xuyang Xiong,Shuoping Ding,Xiufan Liu,Qingqing Jiang,Juncheng Hu
We herein demonstrate the uniform porous hierarchical plate-like BiOCl/2D networks Bi 2 S 3 heterostructures realized by a facile two-step hydrothermal technique. The synthesis involved an anion exchange process by reacting pre-synthesized BiOCl irregular octagonal nanoplates with Na 2 S 2 O 3 ·5H 2 O in an aqueous solution. The experiment results revealed that the 3D plate-like heterostructures were composed of internal BiOCl and outside networks interwoven by 1D Bi 2 S 3 nanorods . Interestingly, the heterostructures had almost the same thickness and the bigger length compared to the precursor BiOCl. We proposed the possible formation mechanism of the composites which involved selective ion-exchange reaction, the following Ostwald ripening process and epitaxial growth . And the crystal lattice matching between the a- or b-axis of tetragonal BiOCl (a = b = 3.89 Å) and the a-axis of orthorhombic Bi 2 S 3 (a = 3.981 Å) could be responsible for the in-situ topotactic transformation. Due to the formation of hetero-nanostructures, the unique spatial architecture features and the existence of oxygen vacancies, the BiOCl/Bi 2 S 3 composites exhibited significantly extended photo-responsive range and improved photocatalytic activity for reduction of Cr VI under visible-light irradiation. Moreover, the possible mechanism of photocatalysis process was investigated. Our work is expected to inspire further attempts for hierarchical and unconventional hetero-nanostructures with unique spatial architecture, which is very promising for photocatalysis and other applications.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）