Advanced Composites and Hybrid Materials
·
2023
·Vol. 6
·期 2
·1-12
·
IF 20.1
Zeng Junling,Xie Wenhao,Zhou Heng,Zhao Tong,Xu Ben Bin,Jiang Qinglong,Algadi Hassan,Zhou Zhenyu,Gu Hongbo
Herein, a nitrogen-doped graphite-like carbon material derived from hybrid phthalonitrile (PN) resin with controllable carbon microstructures including crystalline structures, hybridized carbon configurations, degree of disorder, and nitrogen species such as pyridinic N, pyrrolic N, and graphitic N has been manufactured by high-temperature annealing method. By simply altering these carbon microstructures through annealing temperature, the lowest resistivity of 1.76 Ω·cm at 290 K, the negative MR value of − 6.10% at a magnetic field of 9 T and negative permittivity over − 10 5 at low frequency are achieved in the semiconducting nitrogen-doped graphite-like carbon material. The results confirm the decreasing degree of disorder attained from Raman spectroscopy, the increasing ratio of sp 2 and sp 3 hybridized carbon, i.e., C( sp 2 )/C( sp 3 ), from X-ray photoelectron spectroscopy (XPS), and the rise of charge carrier mobility with increasing the magnetic field from Hall-effect measurement is responsible for the negative MR effect in this nitrogen-doped graphite-like carbon material. The negative permittivity is attributed to the plasma oscillation with delocalized charge carriers by the Drude model and the greatly increasing graphitic N in the carbon microstructures. This work opens a new insight for the applications of carbonized PN resins in the electronic device field.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
Advanced Composites and Hybrid Materials
·
2025
·Vol. 8
·期 2
·1-11
·
IF 21.8
He Qin-yu,Chen Fu-ming,Hu Shu-ting,Zhai Wangjian,Tang Zhilie
Current heavy-metal wastewater treatment methods face significant limitations, creating a need for new technologies. Zero-valent iron (ZVI) shows potential, but the core-shell structure of ZVI is an obstacle due to the low electrical conductivity ( σ ) of its shell, limiting electron transfer from the core to the surface for metal removal reactions. In this study, we enhance the shell’s σ in a pre-magnetized decimeter-sized ZVI plate (MMDZVIP) through reinforced negative magnetoresistance (NMR) effect. Magnetoresistance measurements reveal that MMDZVIP exhibits an NMR effect. MMDZVIP shows a magnetoresistance ratio ( MR ) of -123%, an σ 1.95 times and removal efficiencies 1.91 to 5.18 times that of unmagnetized plates when magnetized to 449 mT. Heavy-metal removal experiments showed nearly 100% removal efficiency at 354 mT, with performance retention above 99.7% after 9 cycles, demonstrating high durability. The mechanism behind the results is as follows: During the removal process, the migration of releasing electrons is aligned to form a current along the normal direction of the MMDZVIP plate. This current is primarily driven by electron consumption on the plate’s surface, where the removal reaction occurs. With pre-magnetization, NMR and Hall effects acted on the releasing electron current and synergistically and significantly enhance the shell's σ . Our work introduces a novel method for enhancing NMR in materials, advancing heavy-metal treatment technologies beyond current limitations.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Meng Li,Jingxue Sun,Xin Zhou,Huaisuo Yao,Bowen Cong,Yingxuan Li,Gang Chen
The introduction of external magnetic field is one of the most widely studied strategies for photogenerated carrier separation in recent years. However, magnetic materials have great disadvantages in terms of photocatalytic performance. Semiconductor materials with magnetic properties are also extremely rare. It is extremely peculiar to research the magnetism of semiconductor photocatalyst triggered by vacancy. Here, the first example of ferromagnetic Bi 2 S 3 is achieved by controlled Bi vacancy (Bi 2 S 3 -V Bi ). The magnetism properties depends largely on the spin polarization of p electrons in S atoms, and its magnetic moment is mainly distributed on S atoms around cation vacancies. Under the induction of external magnetic field, the tunneling of spin-polarized electrons in S-2p orbital makes Bi 2 S 3 -V Bi have negative magnetoresistance effect. The ferromagnetic arrangement of Bi 2 S 3 -V Bi particles can reduce the resistivity and increase the tunneling of electrons. Meanwhile, Lorentz force generated by external magnetic field acts reversely on photogenerated electrons and holes, thus effectively inhibiting the recombination of carriers in photocatalyst. Moreover, the influence of Bi vacancy on Bi 2 S 3 magnetism is investigated by DFT calculation. This study provides a new strategy for effective carrier separation in photocatalysis .
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Chemistry Frontiers
·
2021
·Vol. 5
·期 24
·8275-8280
·
IF 6.482
Xue Han,Zhongnan Guo,Long Chen,Cheng Cao,Fan Sun,Gang Wang,Wenxia Yuan
Two-dimensional (2D) semiconductors with high charge-carrier mobility and exotic quantum properties are of great importance for the design of outstanding electronic devices. Here we report the single crystal growth of van der Waals material Nb2GeTe4, which exhibits very high mobility and unusual transverse negative magnetoresistance (MR) from our transport-property-measurements. Nb2GeTe4 adopts a Te–Nb(Ge)–Te sandwiched layer structure and exhibits a narrow-gap semiconducting behavior. Based on ultraviolet–visible–near infrared (UV-vis-NIR) optical measurement, the optical band gap of Nb2GeTe4 is determined to be around 0.39 eV. The high electron mobility of the Nb2GeTe4 bulk crystal at room temperature, 424.37 cm2 V−1 s−1, is comparable to those of the current state-of-the-art high-mobility layered materials, making Nb2GeTe4 competitive for the design of 2D electronic devices. An anomalous negative magnetoresistance is also observed in Nb2GeTe4 below 10 K with different field dependency, where the maximum MR reaches ∼−31% at 5 K and 5 T.
研究领域:
凝聚态物理
·
材料科学
·
半导体物理
·
纳米电子学
·
量子输运
✓ 已验证
DOI
高影响因子
Nature Physics
·
2016
·Vol. 12
·期 12
·1105-1110
·
IF 18.791
Deng Ke,Wan Guoliang,Deng Peng,Zhang Kenan,Ding Shijie,Wang Eryin,Yan Mingzhe,Huang Huaqing,Zhang Hongyun,Xu Zhilin,Denlinger Jonathan,Fedorov Alexei,Yang Haitao,Duan Wenhui,Yao Hong,Wu Yang,Fan Shoushan,Zhang Haijun,Chen Xi,Zhou Shuyun
Weyl semimetal is a new quantum state of matter1,2,3,4,5,6,7,8,9,10,11,12 hosting the condensed matter physics counterpart of the relativistic Weyl fermions13 originally introduced in high-energy physics. The Weyl semimetal phase realized in the TaAs class of materials features multiple Fermi arcs arising from topological surface states10,11,14,15,16 and exhibits novel quantum phenomena, such as a chiral anomaly-induced negative magnetoresistance17,18,19 and possibly emergent supersymmetry20. Recently it was proposed theoretically that a new type (type-II) of Weyl fermion21,22 that arises due to the breaking of Lorentz invariance, which does not have a counterpart in high-energy physics, can emerge as topologically protected touching between electron and hole pockets. Here, we report direct experimental evidence of topological Fermi arcs in the predicted type-II Weyl semimetal MoTe2 (refs 23,24,25). The topological surface states are confirmed by directly observing the surface states using bulk- and surface-sensitive angle-resolved photoemission spectroscopy, and the quasi-particle interference pattern between the putative topological Fermi arcs in scanning tunnelling microscopy. By establishing MoTe2 as an experimental realization of a type-II Weyl semimetal, our work opens up opportunities for probing the physical properties of this exciting new state.
研究领域:
凝聚态物理学
·
量子材料
·
拓扑材料
·
表面科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）