Article
Physics, Multidisciplinary
Jean-Come Philippe, Alexis Lespinas, Jimmy Faria, Anne Forget, Dorothee Colson, Sarah Houver, Maximilien Cazayous, Alain Sacuto, Indranil Paul, Yann Gallais
Summary: Anisotropic strain selectively affects the role of nematic fluctuations in promoting superconductivity. Our results confirm the significance of nematic fluctuations in electron pairing.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Jaafar N. Ansari, Karen L. Sauer, Igor I. Mazin
Summary: In this study, the effect of Co doping on the real-space nematic fluctuations in BaFe2As2 is investigated by combining nuclear magnetic resonance data with first-principles calculations. It is found that the dynamics of nematic fluctuations are exceptionally slow even in the formally tetragonal phase.
Article
Physics, Multidisciplinary
Haruyasu Sato, Mitsuhiro Akatsu, Ryosuke Kurihara, Yoshiaki Kobayashi, Yuichi Nemoto
Summary: The critical properties originating from degenerate orbitals at the ferro-quadrupole quantum critical point (QCP) in the iron pnictide superconductor Ba(Fe1-xCox)2As2 were investigated through ultrasonic experiments. The temperature dependence of various parameters, such as the elastic soft mode C66, Jahn-Teller energy Delta Q, Weiss temperature Theta Q, and hexadecapole susceptibility ultrasonic attenuation coefficient alpha 66, near the QCP were found to exhibit significant changes. The unconventional critical exponent z nu was observed to be 3 near the QCP, suggesting enhanced quantum fluctuations. These observations indicate the potential key role of order parameter fluctuations in the superconductivity.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Materials Science, Multidisciplinary
Qiang Zou, Mingming Fu, Zhiming Wu, Li Li, David S. Parker, Athena S. Sefat, Zheng Gai
Summary: Electronic inhomogeneities in Co, Ni, and Cr doped BaFe2As2 single crystals were compared in different bulk property regions. Machine learning was used to categorize the inhomogeneous electronic states, revealing different origins and roles. While the relative percentages of electronic states varied in different samples, the total volume fractions were similar.
NPJ QUANTUM MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Yi Huang, Kei Hayashi, Yuzuru Miyazaki
Summary: The effects of cobalt substitution at the Fe-site on the crystal structure, electronic structure, and thermoelectric properties of half-Heusler V(Fe1-xCox)Sb compounds were investigated. The compounds exhibit n-type behavior with decreasing Seebeck coefficient as the cobalt content increases, indicating cobalt substitution as an effective electron dopant for tuning carrier concentration. The optimized carrier concentration leads to the highest power factor at room temperature, making the compounds potential candidates as n-type TE materials for power generation near room temperature.
Article
Chemistry, Physical
Wen-He Jiao, Xiao-Feng Xu, Hao Jiang, Zhu-An Xu, Qing-Hu Chen, Guang-Han Cao
Summary: The study demonstrates the presence of BKT transition and Nelson-Kosterlitz jump in high-quality Ba(Fe0.914Co0.086)(2)As-2 single crystals, along with a non-Hall transverse signal exactly at the superconducting transition, which is likely attributed to the guided motion of unbound vortices.
Article
Materials Science, Multidisciplinary
Long Chen, Cheng Cao, Hongxiang Chen, Jiangang Guo, Jie Ma, Jiangping Hu, Gang Wang
Summary: The crystal structure, magnetic, electronic, and thermal properties of Sr(Fe1-xMnx)(2)As-2 crystals grown by transition metal arsenide flux have been systematically investigated. A miscibility gap and suppression of spin density wave order for certain x values were observed, with no real-space phase separation of Mn and Fe detected. No superconducting signal was observed in the entire composition range.
Article
Materials Science, Multidisciplinary
Teklie Lissanu Tegegne, Gebregziabher Kahsay
Summary: This study investigated the mathematical expressions of temperature and angle dependence of magnetic fields and Ginzburg-Landau characteristics in iron-based superconductors. Phase diagrams were plotted based on experimental values, showing the relationship between various parameters with temperature and angle variations. The theoretical investigation was found to be consistent with the obtained experimental results.
JOURNAL OF MAGNETICS
(2021)
Article
Physics, Applied
Lei Ding, Chaowei Hu, Erxi Feng, Chenyang Jiang, Iurii A. Kibalin, Arsen Gukasov, MiaoFang Chi, Ni Ni, Huibo Cao
Summary: This study summarizes and compares the crystal and magnetic structures of two-dimensional van der Waals MnBi2nTe3n+1 (n = 1, 2, 3, 4) compounds, and discusses the effects of chemical composition on their magnetism. The presence of defects of Bi at the Mn site explains the continuously reduced saturated magnetic moments from n = 1 to n = 4. The experimental critical exponents generally suggest a three-dimensional character of magnetism in all the compounds.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
Anyuan Gao, Yu-Fei Liu, Chaowei Hu, Jian-Xiang Qiu, Christian Tzschaschel, Barun Ghosh, Sheng-Chin Ho, Damien Berube, Rui Chen, Haipeng Sun, Zhaowei Zhang, Xin-Yue Zhang, Yu-Xuan Wang, Naizhou Wang, Zumeng Huang, Claudia Felser, Amit Agarwal, Thomas Ding, Hung-Ju Tien, Austin Akey, Jules Gardener, Bahadur Singh, Kenji Watanabe, Takashi Taniguchi, Kenneth S. Burch, David C. Bell, Brian B. Zhou, Weibo Gao, Hai-Zhou Lu, Arun Bansil, Hsin Lin, Tay-Rong Chang, Liang Fu, Qiong Ma, Ni Ni, Su-Yang Xu
Summary: This study explores the internal structure of topological antiferromagnets, revealing the layer Hall effect and the layer-locked Berry curvature characteristics. The research presents new pathways for detecting and manipulating the internal spatial structure of fully compensated topological antiferromagnets.
Article
Physics, Multidisciplinary
Matthew A. Davenport, Matthew J. Krogstad, Logan M. Whitt, Chaowei Hu, Tyra C. Douglas, Ni Ni, Stephan Rosenkranz, Raymond Osborn, Jared M. Allred
Summary: The study revealed the sudden collapse of three-dimensional order in V1-xMoxO2 compound at x=0.17 and the emergence of a novel frustrated two-dimensional order at x=0.19, with only slight changes in electronic properties. These findings suggest that the two-dimensionality is a result of a novel form of geometric frustration that is essentially structural in origin.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Applied
Chaowei Hu, Makariy A. Tanatar, Ruslan Prozorov, Ni Ni
Summary: MBT is the first intrinsic magnetic topological insulator and can be made ferromagnetic through specific methods. We studied the magnetic dynamics of several ferromagnetic MBT compounds and found a universal slow relaxation behavior, attributing it to irreversible domain movements. The soft nature of ferromagnetic domains was revealed by our magneto-optical measurements.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Multidisciplinary Sciences
Yinming Shao, Ran Jing, Sang Hoon Chae, Chong Wang, Zhiyuan Sun, Eve Emmanouilidou, Suheng Xu, Dorri Halbertal, Baichang Li, Anjaly Rajendran, Francesco L. Ruta, Lin Xiong, Yinan Dong, Alexander S. McLeod, Sai S. Sunku, James C. Hone, Joel Moore, Joe Orenstein, James G. Analytis, Andrew J. Millis, Ni Ni, Di Xiao, D. N. Basov
Summary: This study investigates the optical effects of Chiral Weyl fermions in the Weyl semimetal TaIrTe4 using near-field photocurrent imaging. The analysis of nano-photocurrent maps successfully distinguishes surface- and bulk-related nonlinear contributions, providing evidence for the presence of surface states.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Multidisciplinary
Nathan J. McLaughlin, Chaowei Hu, Mengqi Huang, Shu Zhang, Hanyi Lu, Gerald Q. Yan, Hailong Wang, Yaroslav Tserkovnyak, Ni Ni, Chunhui Rita Du
Summary: This study uses nanoscale quantum imaging of magnetic phase transitions and spin fluctuations in exfoliated MnBi4Te7 flakes with nitrogen-vacancy (NV) centers in diamond. The results reveal the spin transport physics and magnetic domains at the nanoscale, highlighting the unique advantage of NV centers in exploring the magnetic properties of emergent quantum materials.
Article
Chemistry, Multidisciplinary
Tiema Qian, Eve Emmanouilidou, Chaowei Hu, Jazmine C. Green, Igor I. Mazin, Ni Ni
Summary: This study demonstrates the multiple metamagnetic transitions induced by external pressure in topological van der Waals magnets, providing a new avenue for efficient magnetic manipulation in these materials.
Article
Multidisciplinary Sciences
Peng Deng, Christopher Eckberg, Peng Zhang, Gang Qiu, Eve Emmanouilidou, Gen Yin, Su Kong Chong, Lixuan Tai, Ni Ni, Kang L. Wang
Summary: The study finds a universal mesoscopic scattering length (L-s) in quantum anomalous Hall (QAH) materials, which plays a key role in QAH, quantum critical, and insulating regimes, with significant changes in resistance but a consistent L-s value.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Shu Cai, Jinyu Zhao, Ni Ni, Jing Guo, Run Yang, Pengyu Wang, Jinyu Han, Sijin Long, Yazhou Zhou, Qi Wu, Xianggang Qiu, Tao Xiang, Robert J. Cava, Liling Sun
Summary: Here we report the first observation of the concurrent breakdown of the strange metal (SM) normal state and superconductivity at a pressure-induced quantum critical point in Ca-10(Pt4As8)((Fe0.97Pt0.03)(2)As-2)(5) superconductor. The study found that, upon suppressing the superconducting state, the power exponent (alpha) changes from 1 to 2, and the slope of the temperature-linear resistivity per FeAs layer (A(square)) gradually diminishes. At a critical pressure, A(square) and superconducting transition temperature (T-c) go to zero concurrently, indicating a quantum phase transition from a superconducting state with a SM normal state to a non-superconducting Fermi liquid state. Scaling analysis shows that the change of A(square) with T-c follows the relation of T-c similar to (A(square))(0.5), similar to what is seen in other chemically doped unconventional superconductors. These results suggest a simple but powerful organizational principle connecting the SM normal state with high-T-c superconductivity.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Peng Deng, Peng Zhang, Christopher Eckberg, Su Kong Chong, Gen Yin, Eve Emmanouilidou, Xiaoyu Che, Ni Ni, Kang L. Wang
Summary: This study investigates the critical behavior of quantum anomalous Hall (QAH) to normal insulator (NI) and QAH to axion insulator (AXI) transitions in multilayered magnetic topological insulator structures. The authors introduce a new analysis protocol and observe quantized longitudinal resistance and Hall conductance at criticality in both cases. They extract critical exponents for QAH-AXI transitions occurring at magnetization reversals of different magnetic layers, demonstrating that the critical behaviors in QAH transitions are of electronic origin.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Yun Suk Eo, Shouzheng Liu, Shanta R. Saha, Hyunsoo Kim, Sheng Ran, Jarryd A. Horn, Halyna Hodovanets, John Collini, Tristin Metz, Wesley T. Fuhrman, Andriy H. Nevidomskyy, Jonathan D. Denlinger, Nicholas P. Butch, Michael S. Fuhrer, L. Andrew Wray, Johnpierre Paglione
Summary: In this study, we investigate the temperature dependence of electrical resistivity in the spin-triplet superconductor UTe2 along different crystallographic axes. Surprisingly, we find that the resistivities in all current directions exhibit a nearly isotropic transport behavior above the Kondo coherence temperature, despite the highly anisotropic band structure. However, distinct behaviors are observed upon cooling. The temperature dependence of the resistivity along the c axis shows a peak at a much lower temperature than that of the resistivity along the a and b axes, indicating a magnetic origin. Comparing these findings with angle-resolved photoemission spectroscopy experiments provides valuable insights into the underlying electronic structure for building a microscopic model of superconductivity in UTe2.
Article
Materials Science, Multidisciplinary
Tiema Qian, Yueh-Ting Yao, Chaowei Hu, Erxi Feng, Huibo Cao, Igor I. Mazin, Tay-Rong Chang, Ni Ni
Summary: Investigation reveals the effect of magnetic dilution on the magnetism and band topology in MnBi2Te4. Diluting magnetic ions lead to changes in lattice parameters and magnetic properties. External pressure enhances the interlayer antiferromagnetic coupling, and topological phase transitions may occur at specific doping ratios.
Article
Materials Science, Multidisciplinary
Tiema Qian, Morten H. Christensen, Chaowei Hu, Amartyajyoti Saha, Brian M. Andersen, Rafael M. Fernandes, Turan Birol, Ni Ni
Summary: This paper investigates the effect of uniaxial strains along the crystalline a axis on the kagome superconductor CsV3Sb5, revealing a strong competition between the superconducting transition temperature Tc and the charge-density wave transition temperature T-CDW. The study shows that Tc monotonically increases with increasing strain while T-CDW decreases, highlighting the importance of the c-axis lattice parameter as a tuning knob for the phase diagram of CsV3Sb5.
Article
Materials Science, Multidisciplinary
Chaowei Hu, Shang-Wei Lien, Erxi Feng, Scott Mackey, Hung-Ju Tien, Igor I. Mazin, Huibo Cao, Tay-Rong Chang, Ni Ni
Summary: The magnetic topological insulator MnBi4Te7 undergoes a transition from intrinsic antiferromagnetic to ferromagnetic and then ferrimagnetic under Sb doping, attributed to the formation of Mn-(Bi,Mn-Sb) antisites resulting in modified interlayer magnetic interactions. This provides a platform for investigating emergent phenomena such as quantum anomalous Hall effect and Fermi arc states. Additionally, the band topology can be modified to realize a type-I magnetic Weyl semimetal phase with periodic antisites.
Article
Materials Science, Multidisciplinary
Rui Zu, Mingqiang Gu, Lujin Min, Chaowei Hu, Ni Ni, Zhiqiang Mao, James M. Rondinelli, Venkatraman Gopalan
Summary: TaAs and NbAs are early identified Weyl semimetals with intriguing optical properties such as chirality-dependent optical excitations and giant second harmonic generation. By combining spectroscopic ellipsometry and density functional theory, the complete anisotropic dielectric functions of these materials were determined, showing highly anisotropic contributions of Weyl bands at low energies but negligible contributions above 1 eV. Optical techniques for studying Weyl physics require careful assessment to distinguish contributions from Weyl bands and trivial bands.
