Article
Chemistry, Physical
Artem Lynnyk, Roman Puzniak, Luchuan Shi, Jianfa Zhao, Changqing Jin
Summary: The superconducting properties of the CuBa2Ca3Cu4O10+d (Cu-1234) system were investigated, with a high transition temperature and upper critical field. The intra-grain critical current density was high, while the inter-grain critical current density was low due to weak inter-grain connections.
Article
Materials Science, Ceramics
Pawel Peczkowski, Piotr Zachariasz, Marcin Kowalik, Waldemar Tokarz, Sugali Pavan Kumar Naik, Jan Zukrowski, Cezariusz Jastrzebski, Longji Joseph Dadiel, Wojciech Tabis, Lukasz Gondek
Summary: The diffusion of iron into the YBCO matrix is crucial for multilayer systems with YBCO/Fe interfaces. As the Fe content increases, the formation of BaFeO3-delta and iron oxides is observed, leading to a significant suppression of superconductivity in YBCO materials containing more than 7 wt% Fe.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Chemistry, Physical
Stanislav I. Bondarenko, Anatolij I. Prokhvatilov, Roman Puzniak, Jaroslaw Pietosa, Andrey A. Prokhorov, Vladimir V. Meleshko, Valeriy P. Timofeev, Valentin P. Koverya, Dariusz Jakub Gawryluk, Andrzej Wisniewski
Summary: Hydrogenation significantly modified the properties of FeTe0.65Se0.35 single crystals, leading to an increase in critical temperature and critical current density. The structural changes induced by hydrogen diffusion affected the superconducting properties of the crystals.
Article
Materials Science, Multidisciplinary
J. A. Hofer, S. Bengio, N. Haberkorn
Summary: We investigated the impact of Gd magnetic impurities on the superconducting properties of disordered MoNx thin films grown by reactive co-sputtering at room temperature. The addition of Gd suppressed the superconducting critical temperature and affected the temperature dependence of the upper critical field and the vortex dissipation mechanism. These alterations also impacted the instability of the vortex lattice and limited the maximum achievable vortex velocity during dissipation.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Ya-Bin Liu, Yi Liu, Yan-Wei Cui, Si-Qi Wu, Zhi Ren, Guang-Han Cao
Summary: This study investigates the effects of Ni doping on the magnetism and superconductivity in the Eu-containing 112-type system Eu(Fe1-xNix)As-2. The results show that Ni doping suppresses the spin-density wave order and induces superconductivity within a certain range, indicating a weak coupling between superconductivity and Eu spins.
Article
Materials Science, Ceramics
Abderrahmane Raouf Hamoudi, Abdelghani May, Abdelkhalek Henniche, Jia-Hu Ouyang, Alain Guillet
Summary: This study investigated the structural and electrical properties of Ce, Gd-doped YBCO superconductors through X-ray diffraction, Fourier Transform Infrared Spectroscopy, and electrical resistivity measurements. The results showed that the addition of Ce and Gd affected the YBCO system's structure, grain size, surface roughness, and electrical properties. Ce doping improved the critical transition temperature, while Gd doping enhanced the critical current density.
CERAMICS INTERNATIONAL
(2021)
Review
Chemistry, Multidisciplinary
Anna Krzton-Maziopa
Summary: Intercalated layered iron-based monochalcogenides with organic molecules show potential for fine-tuning their magnetic and electrical properties by controlling doping and organic molecule characteristics. Recent progress in intercalation chemistry has led to the discovery of new hybrid inorganic-organic phases with high superconducting transition temperatures.
FRONTIERS IN CHEMISTRY
(2021)
Article
Chemistry, Physical
Manasa Manasa, Mohammad Azam, Tatiana Zajarniuk, Ryszard Diduszko, Tomasz Cetner, Andrzej Morawski, Andrzej Wisniewski, Shiv J. Singh
Summary: The enhanced performance of superconducting FeSe0.5Te0.5 materials with added micro-sized Pb and Sn particles is presented. Pb and Sn additions in small amounts (x = y <= 0.02) improve the transition temperature and metallic nature, while larger additions reduce the transition temperature. Microstructural analysis suggests that larger additions enhance impurity phases and lower coupling between grains, leading to a broadening of the superconducting transition. FeSe0.5Te0.5 samples with 2 wt% of Pb and Sn additions show the best performance in terms of critical current density and pinning force.
Review
Physics, Multidisciplinary
Rong Yu, Haoyu Hu, Emilian M. Nica, Jian-Xin Zhu, Qimiao Si
Summary: Electron correlations play a central role in iron-based superconductors, especially in the normal state and superconducting state with electron filling n similar to 6. The interplay between orbital-selective correlations and electronic nematicity is a key focus of study.
FRONTIERS IN PHYSICS
(2021)
Article
Physics, Condensed Matter
B. Pradhan, P. K. Parida, S. Sahoo
Summary: This study explores the coexistence of different order parameters and pairing symmetry in iron-based superconductors using a two-orbital tight-binding model. Gap equations are derived and solved numerically to investigate the effects of order parameters on each other, with calculations of electronic specific heat, density of states, and band energies revealing second order phase transitions at transition temperatures. The density of states shows interference peaks on either side of the Fermi level corresponding to order parameters with van Hove singularities, and band energies demonstrate a saddle point shift of bands.
SOLID STATE COMMUNICATIONS
(2021)
Article
Physics, Condensed Matter
J. J. Rodriguez Nunez, A. A. Schmidt, I. Tifrea
Summary: We analyzed the superconducting state properties of a two-band self-consistent BCS model with electron band structure suitable for iron-based superconducting materials. The superconducting gap parameters, |Δ(11)(T)| and |Δ(22)(T)|, corresponding to each electron band were investigated as functions of temperature, T, inter-orbital hopping parameter, t(4), and electron doping, N. The two ratios, 2|Δ(0)(11)|/T-c and 2|Δ(0)(22)|/T-c, are not universal and strongly depend on the value of the hopping parameter, t(4). In the case of s(+/-)-wave symmetry, the superconducting state in the system only exists at certain electron doping concentrations, resulting in a complex superconducting phase diagram for iron-based superconducting materials.
EUROPEAN PHYSICAL JOURNAL B
(2023)
Article
Nanoscience & Nanotechnology
Jiannan Song, Zhongtang Xu, Xuming Xiong, Wen Yuan, Chiheng Dong, Qiao Sun, Minghui Tang, Wanping Chen, Huanfang Tian, Jianqi Li, Yanwei Ma
Summary: By using interface engineering and controlling the layer thickness, high-performance FeSe0.5Te0.5 superconducting films with a thickness of up to 2 μm have been successfully prepared. The interface engineering reduces the thickness effect and improves the critical current density. The optimal film thickness is 400 nm, with a critical current density of 1.3 MA/cm² at 4.2K under self-field and 0.71 MA/cm² (H parallel to ab) and 0.50 MA/cm² (H parallel to c) at 9T.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Qiong Wu, Kaiwen Chen, Zihao Zhu, Cheng Tan, Yanxing Yang, Xin Li, Toni Shiroka, Xu Chen, Jiangang Guo, Xiaolong Chen, Lei Shu
Summary: We present the results of muon spin rotation and relaxation (mu SR) measurements on La2(Cu1-xNix)5As3O2 (x = 0.40 and 0.45), a recently discovered layered Cu-based superconductor. Transverse-field mu SR experiments reveal that the temperature dependence of superfluid density can be best described by a two-band model. The zero-temperature magnetic penetration depth lambda ab(0) for x = 0.40 and 0.45 were found to be 427(1.7) nm and 422(1.5) nm, respectively. These compounds lie between unconventional and standard BCS superconductors on the Uemura plot. Zero-field mu SR measurements do not provide evidence of time-reversal symmetry breaking in the superconducting state.
Article
Physics, Applied
He Huang, Chao Yao, Chiheng Dong, Xianping Zhang, Dongliang Wang, Shifa Liu, Zhe Cheng, Yanchang Zhu, Yanwei Ma
Summary: Using the EBSD technique, the microstructure of hot-pressed (HP) and flat-rolled (FR) Ba-122 tapes was analyzed. The results indicated that HP tapes exhibited better texture and grain connectivity, while FR tapes had smaller grain size. It is recommended to find a balance point that promotes grain orientation and maintains moderate grain size to improve the transport properties of IBS tapes further.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Ceramics
Ana Harabor, Petre Rotaru, Novac Adrian Harabor, Petr Nozar, Andrei Rotaru
Summary: A composite material with superconducting properties was obtained by sintering YBa2Cu3O7-x doped with Ag2O at 960 degrees C and employing a special cooling program. XRD and SEM analysis confirmed the preferential orientation of YBa2Cu3O7-x crystallites. The dimensions of YBCO-123 crystallites were found to be dependent on Ag content. TGA showed that total mass loss during heating was influenced by Ag content.
CERAMICS INTERNATIONAL
(2023)
Article
Physics, Multidisciplinary
Dumitru Calugaru, Aaron Chew, Luis Elcoro, Yuanfeng Xu, Nicolas Regnault, Zhi-Da Song, B. Andrei Bernevig
Summary: A new theoretical technique is introduced for identifying materials with flat bands and constructing perfectly flat bands. The study shows that these flat bands can lead to exotic phases and special properties, and are useful for investigating strong electron interactions.
News Item
Physics, Multidisciplinary
Kun Jiang, Jiangping Hu
Summary: The article discusses two demonstrations of a superconducting diode effect, showing the possibility of equivalent behavior in superconductors through different mechanisms.
Review
Multidisciplinary Sciences
Kun Jiang, Tao Wu, Jia-Xin Yin, Zhenyu Wang, M. Zahid Hasan, Stephen D. Wilson, Xianhui Chen, Jiangping Hu
Summary: This review discusses the recent progress on the experimental and theoretical studies of kagome superconductors AV(3)Sb(5), including the electronic properties, charge density wave state, time-reversal symmetry breaking, and superconducting properties. The authors aim to stimulate an expanded search for unconventional kagome superconductors.
NATIONAL SCIENCE REVIEW
(2023)
Article
Physics, Multidisciplinary
Xingyu Jiang, Mingyang Qin, Xinjian Wei, Li Xu, Jiezun Ke, Haipeng Zhu, Ruozhou Zhang, Zhanyi Zhao, Qimei Liang, Zhongxu Wei, Zefeng Lin, Zhongpei Feng, Fucong Chen, Peiyu Xiong, Jie Yuan, Beiyi Zhu, Yangmu Li, Chuanying Xi, Zhaosheng Wang, Ming Yang, Junfeng Wang, Tao Xiang, Jiangping Hu, Kun Jiang, Qihong Chen, Kui Jin, Zhongxian Zhao
Summary: Superconductivity is related to the strange-metal state, and the resistivity in the strange metal significantly depends on the superconducting transition temperature. Unconventional superconductors usually exhibit a linear temperature dependence of resistivity (T-linear) in the low-temperature limit. The understanding of the relationship between the strange metal and superconductivity is crucial for further theoretical development, but comprehensive studies are lacking due to the difficulty in controlling the superconducting state. In this study, a typical strange-metal behavior, T-linear resistivity, linear-in-field magnetoresistance, and universal scaling of magnetoresistance, is observed in FeSe. The relationship between the T-linear resistivity coefficient and the critical temperature suggests a universal mechanism underlying T-linear resistivity and unconventional superconductivity.
Article
Multidisciplinary Sciences
Zhendong Jin, Yangmu Li, Zhigang Hu, Biaoyan Hu, Yiran Liu, Kazuki Iida, Kazuya Kamazawa, Matthew B. Stone, Alexander I. Kolesnikov, Douglas L. Abernathy, Xiangyu Zhang, Haiyang Chen, Yandong Wang, Chen Fang, Biao Wu, Igor A. Zaliznyak, John M. Tranquada, Yuan Li
Summary: A large body of knowledge about magnetism is obtained from models of interacting spins on magnetic ions. However, proposals beyond the ionic picture are rare and rarely verified. In this study, using inelastic neutron scattering, it is found that the fundamental magnetic units in the near-ferromagnet MnSi are extended molecular orbitals consisting of three Mn atoms, contrasting the ionic picture. This discovery provides important insights into both MnSi and a broad range of magnetic quantum materials.
Article
Materials Science, Multidisciplinary
Yipeng An, Juncai Chen, Zhengxuan Wang, Jie Li, Shijing Gong, Chunlan Ma, Tianxing Wang, Zhaoyong Jiao, Ruqian Wu, Jiangping Hu, Wuming Liu
Summary: In this study, a new kagome magnesium triboride (MgB3) superconductor is predicted, with a calculated critical temperature of about 12.2 K and 15.4 K under external stress, which is potentially the highest among the reported diverse kagome-type superconductors. Various exotic physical properties of the system, including van Hove singularity, flat-band, multiple Dirac points, and nontrivial topology, are revealed. The topological and nodal superconducting nature of MgB3 is unveiled using a recently developed symmetry indicators method. This study suggests that MgB3 can serve as a new platform to explore exotic physics in the kagome structure and search for more superconductors and topological materials with XY3-type kagome lattice.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Inorganic & Nuclear
Ying Zhou, Long Chen, Yuxin Wang, Jinfeng Zhu, Zhongnan Guo, Chen Liu, Zhiying Guo, ChinWei Wang, Han Zhang, Yulong Wang, Ke Liao, Youting Song, Jia-ou Wang, Dongliang Chen, Jie Ma, Jiangping Hu, Gang Wang
Summary: A new series of compounds, ANi5Bi5.6+delta (where A = K, Rb, and Cs), have been discovered with a quasi-one-dimensional (Q1D) [Ni5Bi5.6+delta]- double-walled column and a coaxial inner one-dimensional Bi atomic chain. The compounds exhibit metallic behaviors with strong electron correlation, and the Sommerfeld coefficient is enhanced with the increasing cationic radius. The substitution of Ni for Mn in ANi5Bi5.6+delta results in enhanced intercolumn distances and strong diamagnetic susceptibilities.
INORGANIC CHEMISTRY
(2023)
Article
Multidisciplinary Sciences
Lun Jin, Nicodemos Varnava, Danrui Ni, Xin Gui, Xianghan Xu, Yuanfeng Xu, B. Andrei Bernevig, Robert J. Cava
Summary: Electronic structure calculations show that Sr2FeSbO6 double perovskite has a flat-band set just above the Fermi level, which includes contributions from ordinary subbands with weak kinetic electron hopping and a flat subband attributed to lattice geometry and orbital interference. Electron-doped Sr2-xLaxFeSbO6 samples (0 ≤ x ≤ 0.3) were synthesized to place the Fermi energy in that flat band, and their magnetism and crystal structures were analyzed. The dominant spin coupling changes from antiferromagnetic to ferromagnetic upon electron doping, but it remains unclear which subband or combination is responsible for this behavior.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Multidisciplinary Sciences
Zhongyi Zhang, Shengshan Qin, Jiadong Zang, Chen Fang, Jiangping Hu, Fu-Chun Zhang
Summary: The presence of Dzyaloshinskii-Moriya (DM) interaction in limited noncentrosymmetric materials leads to unique spin textures and exotic chiral physics. The emergence of DM interaction in centrosymmetric crystals has the potential to greatly enhance material realization. In this study, we demonstrate that an itinerant centrosymmetric crystal respecting a nonsymmorphic space group can serve as a new platform for the DM interaction. Our findings reveal the role of nonsymmorphic symmetries in influencing magnetism and suggest that nonsymmorphic crystals can be promising platforms for designing magnetic interactions.
Article
Physics, Multidisciplinary
Kai Zhang, Chen Fang, Zhesen Yang
Summary: In this study, the concept of dynamical degeneracy splitting is introduced to explain the anisotropic decay behaviors in non-Hermitian systems. It is shown that systems with dynamical degeneracy splitting exhibit frequency-resolved non-Hermitian skin effect and anomalous behavior in Green's function, resulting in uneven broadening in spectral function and anomalous scattering. The directional invisibility based on wave packet dynamics is proposed to investigate the geometry-dependent skin effect in higher dimensions. This work provides a guiding principle for exploring novel physical phenomena arising from the non-Hermitian skin effect.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Aaron Chew, Yijie Wang, B. Andrei Bernevig, Zhi-Da Song
Summary: We demonstrate the emergence of higher-order topological superconductivity in twisted bilayer graphene by introducing spin-singlet or spin-triplet superconductivity. The appearance of multiple copies of C2zT-protected Majorana Kramers pairs is observed at corners on pairing domain walls. The topological properties originate from the absence of a lattice support in the single-valley band structure of twisted bilayer graphene, which is protected by C2zT and approximate particle-hole symmetry P. We prove that any pairing term preserving valley-U(1), spin-SU(2), time-reversal, C2zT, and P can result in a higher-order topological superconductor. The stability of the corner states is verified even when P is weakly broken, which is applicable in experimental setups. Detection of these effects is proposed through the fractional Josephson effect in a TBG-TSC Josephson junction.
Article
Materials Science, Multidisciplinary
Lun-Hui Hu, Chunyu Guo, Yan Sun, Claudia Felser, Luis Elcoro, Philip J. W. Moll, Chao-Xing Liu, Andrei Bernevig
Summary: In this study, a hierarchical structure of quasisymmetries and their corresponding nodal structures in the chiral crystal material CoSi are revealed through two different approaches of perturbation expansions. Quasisymmetries are found to play a crucial role in the physical responses of the system and can protect the existence of nodal planes.
Article
Materials Science, Multidisciplinary
Yi Zhang, Yuhao Gu, Hongming Weng, Kun Jiang, Jiangping Hu
Summary: We investigate the strong electron-electron correlation effects in two-dimensional van der Waals materials Nb3X8 (X = Cl, Br, I). The monolayers Nb3X8 are close to the strong correlation limit and can be described by a half-filled single band Hubbard model with U/W ratio approximating to 5-10. Mott and magnetic transitions are calculated using the slave boson mean-field theory, and a dx2-y2 + idxy superconducting pairing instability is found upon doping the Mott state. A tunable bilayer Hubbard system is also constructed for two sliding Nb3X8 layers, showing a crossover between band insulator and Mott insulator.
Article
Materials Science, Multidisciplinary
Kun Jiang, Ziyue Qi, Hongming Weng, Jiangping Hu
Summary: In this study, we examine the properties of obstructed atomic insulators under correlation and find that the obstruction properties persist even at high correlation levels. This suggests that the obstructed atomic insulator phase can transition to its Mott phase seamlessly without undergoing a Mott transition.
Article
Materials Science, Multidisciplinary
Zhongyi Zhang, Jie Ren, Yang Qi, Chen Fang
Summary: This article investigates intrinsic topological superconductors and discovers that they can be classified and constructed in three dimensions by using both point-group and time-reversal symmetries for protection, without the need for external magnetic fields, defects, or heterostructures. The researchers establish a complete classification by enumerating distinct stacking methods, or irreducible building blocks, which represent minimal anomalous surface states of nth-order topological superconductors. The findings provide a unified description of potential surface anomalies away from high-symmetry points/lines using the homotopy group of the surface mass field.
