JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 107
·期 2
·968-978
·
IF 3.9
Qingkai Tang,Xinhua Zhu
Half-metallic ferromagnets (HMFs) are highly desirable materials for applications in spintronics because of their semiconducting behavior for one spin projection and metallic nature for the other. To operate spintronic devices at room temperature (RT), HMFs should simultaneously have a large saturation magnetization ( M S ), high magnetic Curie temperature ( T C ), and a wide half-metallic gap. However, HMFs that simultaneously fulfill these three criteria are rare. In this work, we report for the first time on the ferrimagnetic double perovskite oxides of Sr 2 CrHfO 6 (SCHO) with a magnetic T C up to 545 K due to the strong Cr 3+ (↑)Cr 4+ (↓) antiferromagnetic spin interactions. The combined experimental results confirmed that the SCHO powders crystallized in an orthogonal crystal structure with Pnma symmetry. The SEM images demonstrate that the powders exhibit a spherical morphology with particle sizes between 150 and 250 nm. XPS spectra verified the presence of Sr 2+ , Cr 3+ /Cr 4+ , and Hf 4+ /Hf x+ (x < 4) ions in the SCHO powder. Oxygen was present as lattice oxygen and adsorbed oxygen species. At 2 K, the SCHO powder exhibited ferrimagnetic behavior with M S of 0.11 μ B /f. u and a magnetic coercive field of 290 Oe. The SCHO ceramics displayed a normal butterfly-like magnetoresistance-magnetic field (MR-H) curve at 2 K due to the intergranular tunneling effect, and the MR (2 K, 7 T) value was −2.05%. The temperature dependence of the resistivity of the SCHO ceramics revealed their semiconducting nature, and the electrical transport data in the temperature range 2−800 K were well fitted by the Mott's variable-range hopping model, thermal activation model, and small polaron hopping model. Optical measurements demonstrate that the SCHO powders have a direct optical bandgap of 2.25 eV in the visible light window. Having both high T C and a direct optical bandgap (2.25 eV) makes SCHO oxides attractive for use in advanced spintronic devices and solar cells.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
Tungsten
·
2020
·Vol. 2
·期 3
·251-260
·
IF 0
Liu Xiao-Lei,Wang Hong-Yuan,Su Hao,Yu Zhen-Hai,Guo Yan-Feng
The intriguing quasiparticles in solids, known as Dirac, Weyl, and Majorana fermions, etc. with properties akin to those theoretically predicted but never realized in high-energy physics, have excited intensive research activities in recent years. The transition metal dipnictides are attractive because of their extremely large magnetoresistance that is usually attributed to the carrier compensation effect. We briefly review herein the crystal growth, magneto-transport measurements, and theoretical studies of tantalum dipnictides TaAs 2 and TaP 2 , with the emphasis being put on discussion of the nontrivial topological states in both materials. The analysis of quantum oscillations of the magnetoresistance unveils nonzero Berry phase. The chiral negative longitudinal magnetoresistance further points to possible Weyl state, which was recently theoretically suggested as the result of the magnetic field-induced Zeeman splitting effect no matter how large the field is. The analysis of these intriguing behaviors could brush up our understanding about the family of materials and would be valuable for future work on investigating the magnetic field-induced topological phase transition in such semimetals.
研究领域:
凝聚态物理
·
材料科学
✓ 已验证
DOI
ACS Applied Energy Materials
·
2019
·
IF 0
Xiaohui Ren,Zhongjun Li,Hui Qiao,Weiyuan Liang,Huating Liu,Feng Zhang,Xiang Qi,Yundan Liu,Zongyu Huang,Du Zhang,Jianqing Li,Jianxin Zhong,Han Zhang
Two-dimensional (2D) material with thickness down to the atomic state is regarded as able to expose more active sites and achieve much higher catalytic efficiency than its bulk counterpart. Recent investigated semi-metallic antimony (Sb) demonstrates high charge carrier density and environmental stability toward prospective electrocatalytic performance. In this work, we adopt a favorable liquid exfoliation approach to produce few-layer antimonene and implement it as a metal-free electrocatalyst for water splitting. Few-layer antimonene nanosheets have been realized with preferable bifunctional electrocatalytic activity in association with structural robustness; meanwhile, the catalytic performance and charge transfer behavior of an integrated three-electrode system have also been uncovered. In addition to bifunctional catalytic ability, few-layer antimonene shows a low catalytic threshold because of the inherent characteristics derived from semi-metallic layered materials. It is further anticipated that the present work contributes to extendable investigations about the catalytic performance of antimonene nanosheets and related electrocatalytic devices.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
ADVANCED MATERIALS
·
2018
·Vol. 30
·期 22
·1707152
·
IF 21.95
Jiawei Lai,Xin Liu,Junchao Ma,Qinsheng Wang,Kenan Zhang,Xiao Ren,Yinan Liu,Qiangqiang Gu,Xiao Zhuo,Wei Lu,Yang Wu,Yuan Li,Ji Feng,Shuyun Zhou,Jian-Hao Chen,Dong Sun
Photodetectors based on Weyl semimetal promise extreme performance in terms of highly sensitive, broadband and self-powered operation owing to its extraordinary material properties. Layered Type-II Weyl semimetal that break Lorentz invariance can be further integrated with other two-dimensional materials to form van der Waals heterostructures and realize multiple functionalities inheriting the advantages of other two-dimensional materials. Herein, we report the realization of a broadband self-powered photodetector based on Type-II Weyl semimetal T d -MoTe 2 . The prototype metal–MoTe 2 –metal photodetector exhibits a responsivity of 0.40 mA W −1 and specific directivity of 1.07 × 10 8 Jones with 43 μs response time at 532 nm. Broadband responses from 532 nm to 10.6 μm are experimentally tested with a potential detection range extendable to far-infrared and terahertz. Furthermore, we identify the response of the detector is polarization angle sensitive due to the anisotropic response of MoTe 2 . The anisotropy is found to be wavelength dependent, and the degree of anisotropy increases as the excitation wavelength gets closer to the Weyl nodes. In addition, with power and temperature dependent photoresponse measurements, the photocurrent generation mechanisms are investigated. Our results suggest this emerging class of materials can be harnessed for broadband angle sensitive, self-powered photodetection with decent responsivities.
研究领域:
凝聚态物理
·
光电子学
·
量子材料
·
纳米技术
·
二维材料
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2024
·Vol. 58
·期 6
·065107
·
IF 3.1
Liu Yang,Dong Wang,Jie Li,Pengdong Wang,Xingang Hou,Keqin Tang,Lin Wang,Zhuo Dong,Kai Zhang
Topological nodal-line semimetals (TNLSs) can be understood as a collection of two-dimensional Dirac Fermions along the line, which endows high mobility and extraordinary electrical transport in all directions near the Dirac points. Furthermore, the band geometry at the Fermi level can be easily modified by external field excitations. These features can bring intriguing properties, such as superconducting, Lifshitz transitions, strong light-matter interaction, and high photoconductivity, supporting low-energy carrier excitations and enhanced optical absorption at terahertz (THz) frequency ranges. Herein, a novel TNLS InNbS2-based THz photodetector was fabricated and the photoresponse within 0.02–0.3 THz was explored. A fast response speed of 15.4 μs, a maximum responsivity (RI) of 1.4 A W–1, and a superb noise equivalent power (NEP) of 11.5 pW Hz−1/2 were achieved at 0.11 THz under a bias voltage of 100 mV due to the high photoconductive gain. Meanwhile, the high-resolution THz transmission imaging of a metallic rainbow was carried out to demonstrate the THz imaging functionality. These results explore new avenues for utilizing TNLSs in THz photodetection and establish a basis for the application in the THz field.
研究领域:
材料科学
·
光电子学
·
凝聚态物理
✓ 已验证
DOI
高影响因子
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
Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 29
·11065-11072
·
IF 0
Qian Zhang,Ying Zhou,Fang Wang,Fan Dong,Wei Li,Haimin Li,Greta R. Patzke
Elemental photocatalysts have recently been proposed as interesting materials to be used as alternatives to conventional semiconductor compounds. In this study, we demonstrate that not only elements with semiconducting properties are photocatalytically active by introducing semimetallic bismuth for the photooxidation of NO. Black Bi films were prepared via an electrochemical deposition approach. Both density functional theory (DFT) calculations and temperature dependence electrical resistivity measurements pointed out that the obtained films exhibited semimetallic behavior. The Bi films were easily oxidized upon exposure to air. However, electrochemical reduction of the surface amorphous oxide layer led to a more than 4-fold enhancement of the photocurrent density of the Bi films. The detection of hydroxyl radicals with electron spin resonance (ESR) investigations further confirmed the photogeneration of electrons and holes. A 37.7% removal ratio of NO over Bi films was observed under UV light irradiation with no significant reduction of photocatalytic activity after five cycles. Given that the conduction and valence bands of semimetallic Bi overlap, the associated excitation processes are more complex in comparison with semiconductor photocatalysts, thereby indicating a different photocatalytic mechanism. The present study points out new directions for developing semimetallic photocatalysts.
研究领域:
材料科学
·
环境催化
·
物理化学
·
表面科学
·
无机功能材料
✓ 已验证
DOI
Energy & Environmental Science
·
2022
·Vol. 15
·期 4
·1601-1610
·
IF 39.714
Hongguan Li,Shuanlong Di,Ping Niu,Shulan Wang,Jing Wang,Li Li
Single atom metal–nitrogen–carbon materials have shown immense potential for the oxygen reduction reaction (ORR) while the development of durable catalysts with high reactivity remains a great challenge. Herein, by rationally designing a diatomic catalyst Fe/Zn–N–C based on theoretical screening, we propose a unique half-metallic electronic structure induced by cooperation of Fe and Zn. This structure populates spontaneous spin-polarized conduction electrons at the Fermi level, resulting in an enhancement in free O2 capture and bonding. Meanwhile, the active center of FeN4 is well preserved with Zn–N as the sacrificial bond during the ORR. Fe/Zn–N–C therefore achieved remarkable ORR activities in both acidic and alkaline media as well as impressive long-term durability that outperform most state-of-the-art catalysts and commercial benchmarks. This work advances our fundamental knowledge of the structure–performance relationship for ORR electrocatalysts, which could potentially inspire the exploration of high-performance candidates via electronic structure modulation.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Yong Yang,Zheng Tang,Baojing Zhou,Jinyou Shen,Huichao He,Amjad Ali,Qin Zhong,Yujie Xiong,Chao Gao,Ahmed Alsaedi,Tasawar Hayat,Xiaoyong Wang,Yong Zhou,Zhigang Zou
An absolute metal-free in-plane heterosystem consisting of g-C 3 N 4 as scaffold and embedded half-metallic C(CN) 3 as cocatalysts was conceptually designed for photoconversion of CO 2 . The no-slot joint between half-metallic C(CN) 3 and g-C 3 N 4 through covalent bonding generates a unique two-dimensional, π-conjugated hybrid structure, allowing obstacle-free transferring of the photogenerated electrons in g-C 3 N 4 into C(CN) 3 via an intrinsic driving force. Our theoretical calculations together with the in-situ Fourier transform infrared spectra indicate that the most negative charge distribution and binding energy with CO 2 for C(CN) 3 allow outstanding capture and chemical activation capacity toward CO 2 , and subsequently enable the optimized heterosystem to exhibit highly efficient and selective photocatalytic reduction of CO 2 into CO, 7.8 and 1.9 times those produced with pristine and Pt-modified g-C 3 N 4 , respectively. The no-slot joint of organic half-metal cocatalysts with g-C 3 N 4 may open up new opportunities for metal-free, polymer-based photocatalytic systems for CO 2 conversion and solar fuel generation.
研究领域:
材料科学
·
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2024
·
IF 7.1
Shudi Yu,Nannan Zhang,Jie Li,Jiongting Yin,Yong Wang,Zhengying Wu,Yangping Zhang,Yukou Du
A metal–organic framework (MOF) embedded by transition metal sulfide (TMS) particles is one of the promising electrocatalyst candidates for overall water splitting (OWS) due to the large surface area and abundant active sites from the MOF precursor, as well as the tunable electronic structure and higher intrinsic conductivity of TMS. More importantly, its self-restructuring under alkaline conditions will lead to the chemical composition and phase evolution of the catalyst surface, which is the source of its further enhanced catalytic activity. A semi-MOF (labeled as Co@Ni/Fe-MS/MOF) with MOF as the semisacrificial template and a TMS particle as the guest was designed by exercisable and universal heteroatomic Co doping and partial vulcanization. The TMS/MOF heterostructure establishes an ideal bridge for electron transfer. Simultaneously, the dopant Co and the synergistic effect of multiple metal sites also effectively regulate the charge environment around the catalytic sites, which jointly improve the adsorption/desorption kinetics of the reaction intermediates. As a result, Co@Ni/Fe-MS/MOF exhibits a distinguished overpotential (η10 = 229 mV for OER, η10 = 174 mV for HER) and Tafel slope (52.37/114.35 mV dec–1 for OER/HER), as well as unrivaled long-term durability (80 h for OWS). Moreover, the two-electrode Co@Ni/Fe-MS/MOF ∥ Co@Ni/Fe-MS/MOF cell illustrates a small cell voltage of 1.54 V to achieve a power of 10 mA cm–2. Impressively, this superior OER property comes from the three-layer sandwich structure restructured by the hybrid semi-MOFs in the alkaline environment as the true active sites. This work aspired to regulate the electronic structure of the catalyst, induce synergistic effects, and shed light on the preparation of hybrid semi-MOF materials by heterogeneous interface engineering, doping engineering, and phase evolution.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Laser & Photonics Reviews
·
2025
·
IF 10
Ruixue Bai,Xiaoshan Du,Rui Zhou,Yaojie Zhu,Xilin Zhang,Yulun Liu,Zuowei Yan,Wei Li,Hui Ma,Chongyun Jiang
Weyl semiconductors, combining the high tunability features of semiconductors with the exotic topological properties of Weyl materials, are of great significance for fundamental physics studies and functional topological devices. Despite the potential theoretical implications, few Weyl semiconductors are experimentally discovered. Chirality is an extraordinary feature of Weyl nodes, which can give rise to helicity-resolved photocurrents, known as the circular photogalvanic effect (CPGE). Here, this work discloses the surface CPGE in nonsymmorphic-symmetry ZrGeTe 4 semiconductors via a specific excitation and detection geometry, demonstrating that it originates from asymmetric helicity-dependent optical transitions between two Kramers–Weyl nodes in the conduction and valence bands. Wavelength-dependent experiments support the chirality-related Weyl features of the CPGE in ZrGeTe 4 semiconductors. It is experimentally confirmed that the Weyl-related surface CPGE is an intrinsic phenomenon that can be flexibly tuned with an in-plane electric field. The work provides a new platform for designing spintronic, optoelectronic, and quantum devices by integrating the advantages of topological materials with versatile semiconductors.
研究领域:
凝聚态物理
·
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 107
·期 5
·3252-3264
·
IF 3.9
Qingkai Tang,Xinhua Zhu
Half-metallic ferromagnets (HMFs) exhibit semiconductor behavior for one spin projection and metal characteristics for the other, which have promising applications in spintronics. It is a great challengeable for HMFs to have wide spin energy gap, large saturation magnetization ( M S ), and high Curie temperature ( T C ) simultaneously. Here, we report the Sr 1.5 Mn 0.5 Fe 0.5 Hf 1.5 O 6 (SMFHO) double perovskite compounds synthesized by solid-state reaction and display a magnetic T C up to 804 K due to the strong Mn 3+ (↑)Fe 3+ (↑) spin interactions, which is the reported record in perovskite-type HMFs so far. The measured M S value at 300 K was 4.87 μ B /f.u., and it further increased up to 6.09 μ B /f.u. at 2 K. The SMFHO powders exhibited butterfly-shaped magnetoresistance (MR)–H curve at 2 K, and the MR (2 K, 7 T) value was measured as −3.86% due to the intergranular magnetic tunneling effect. Variation of the resistivity of the SMFHO ceramics versus temperature exhibits a semiconductor behavior, and the electrical transport properties of the SMFHO ceramics are well studied by Mott's range jump model, thermally activated semiconductor conductance model and small polaron jumping model, respectively. The optical absorption spectrum of the SMFHO powders demonstrates an indirect optical bandgap of 3.56 eV. Our present work demonstrates the intriguing properties of the SMFHO oxides where high T C , wide energy gap, and large M S value are preserved at the same time, which open the way to their promising applications in advanced spintronic devices at or beyond room temperature.
研究领域:
材料科学
·
凝聚态物理
✓ 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）