Article
Chemistry, Physical
Yujun Zhang, Jiahui Chen, Keisuke Ikeda, Kohei Yamagami, Yue Wang, Yongseong Choi, Akira Yasui, Jing Ma, Yuanhua Lin, Cewen Nan, Hiroki Wadati
Summary: In this study, the magnetism and electronic structure changes across the AFM-FM transition of Ni-doped FeRh epitaxial thin films were investigated using XMCD and HAXPES techniques. The results showed that the remnant FM phase at low temperature possesses a smaller Rh moment than the normal FM phase, while an increase of Rh 4d density of state at the Fermi level and a possible well-screened Ni 2p state were found in the FM phase. In addition, the FM fluctuation of the inter-site Fe-Fe exchange coupling within the AFM phase was observed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Multidisciplinary
Aravind Raji, Guillaume Krieger, Nathalie Viart, Daniele Preziosi, Jean-Pascal Rueff, Alexandre Gloter
Summary: The structural and charge distribution of NdNiO2 thin films with and without charge ordering (CO) are studied. The capped samples show Ni1+ and have a stabilized infinite-layer structure, while the uncapped samples exhibit an increase in the o-o-p parameter, indicating the presence of Ni2+. The results suggest a possible link between charge ordering and oxygen re-intercalation in infinite-layer nickelate thin films.
Review
Physics, Condensed Matter
Curran Kalha, Nathalie K. Fernando, Prajna Bhatt, Fredrik O. L. Johansson, Andreas Lindblad, Hakan Rensmo, Leon Zendejas Medina, Rebecka Lindblad, Sebastian Siol, Lars P. H. Jeurgens, Claudia Cancellieri, Kai Rossnagel, Katerina Medjanik, Gerd Schonhense, Marc Simon, Alexander X. Gray, Slavomir Nemsak, Patrick Loemker, Christoph Schlueter, Anna Regoutz
Summary: Hard x-ray photoelectron spectroscopy (HAXPES) is a crucial technique for material characterization, with a growing number of specialized techniques utilizing hard x-rays to provide transformative insights into the nature of materials. This paper offers a historical perspective on HAXPES, from its early developments to state-of-the-art instrumentation, and aims to provide an overview of the technique in 2020 and potential future developments.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Chemistry, Physical
Makoto Takayanagi, Takashi Tsuchiya, Shigenori Ueda, Tohru Higuchi, Kazuya Terabe
Summary: The combination of in situ HAXPES and electrochemical measurements allows for the separation and quantitative evaluation of reversible Li+, irreversible Li2WO4 formation, and irreversible Li+ trapping. The inserted Li+ conversion ratios of reversible Li+, irreversible Li2WO4 formation, and irreversible Li+ trapping were clarified to be 41.4%, 50.9%, and 7.7%, respectively.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Pamella Vasconcelos Borges Pinho, Alain Chartier, Frederic Miserque, Denis Menut, Jean-Baptiste Moussy
Summary: The influence of epitaxial strain on the electronic structure of alpha-Cr2O3(0001) thin films is investigated through X-ray photoemission spectroscopy and crystal field multiplet calculations. In-plane lattice strain distorts the CrO6 octahedron and splits the 3d orbital triplet t(2g) into a(1) + e orbitals. Understanding these crystal field variations is crucial for tuning the physical properties of alpha-Cr2O3 thin films.
MATERIALS RESEARCH LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Afroz Khan, F. Rahman, Razia Nongjai, K. Asokan
Summary: In this study, pure and Fe-doped indium oxide nanostructured thin films were deposited by pulsed laser on quartz substrates. The films exhibit polycrystalline structures with cubic bixbyite geometry, arranged in semi-regular patterns with low surface roughness. Fe doping leads to a decrease in band gap and optical transmittance, as well as an increase in resistivity and a decrease in carrier concentration and mobility. The films exhibit n-type semiconducting behavior and follow the Mott-VRH conduction model at lower temperatures.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Priyanka Gupta, Vandana Rathore, Sophia Sahoo, Supriyo Majumder
Summary: In this study, we have investigated the electronic structure of 10% Mn doped SnO2 thin film on Si(001) substrate. X-ray diffraction confirmed the single-phase growth with decreasing crystallite size upon Mn doping. X-ray photoemission spectroscopy revealed the presence of dominant Sn4+ and minor Sn2+ valence states, which resulted from oxygen deficiency and led to Mn4+ and Mn2+ states in the film. Our resonant photoemission study explained the origin of different energy bands near the Fermi level, which can be further manipulated for various fundamental properties.
Article
Chemistry, Multidisciplinary
Khalid Quertite, Hanna Enriquez, Nicolas Trcera, Yongfeng Tong, Azzedine Bendounan, Andrew J. Mayne, Gerald Dujardin, Pierre Lagarde, Abdallah El Kenz, Abdelilah Benyoussef, Yannick J. Dappe, Abdelkader Kara, Hamid Oughaddou
Summary: The authors reported the first experimental evidence of silicene nanoribbons on an insulating NaCl thin film, representing a major breakthrough in studying the intrinsic properties of silicene and other 2D materials grown on metal surfaces.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Antoine Laine, Rahul Parmar, Matteo Amati, Luca Gregoratti, Gregory Su, Ting Xu, Miquel Salmeron
Summary: Researchers have found that graphene can serve as an x-ray and electron transparent substrate, reducing radiation damage to oxide thin films. This discovery opens up possibilities for the development of experimental setups with limited sample damage.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Weon Cheol Lim, Jitendra Pal Singh, Younghak Kim, Jonghan Song, Keun Hwa Chae, Tae-Yeon Seong
Summary: The study shows that thermal annealing significantly affects the properties of zinc oxide thin films, including relaxation of stress, variation in optical band-gap, and occurrence of vacancies and defects. These changes are revealed through X-ray techniques, providing a better understanding of the performance changes in zinc oxide films.
Article
Materials Science, Multidisciplinary
Fatima Alarab, Karol Hricovini, Berengar Leikert, Laurent Nicolai, Mauro Fanciulli, Olivier Heckmann, Christine Richter, Lucie Prusakova, Zdenek Jansa, Pavol Sutta, Julien Rault, Patrick Lefevre, Michael Sing, Matthias Muntwiler, Ralph Claessen, Jan Minar
Summary: The electronic properties of SrTiO3 doped with Ni impurities were investigated through a combination of photoelectron spectroscopy and first-principles calculations, confirming the formation of localized 3d-impurity bands in the band gap of SrTiO3.
Article
Nanoscience & Nanotechnology
Dirk Hauschild, Linsey Seitz, Saba Gharibzadeh, Ralph Steininger, Nan Jiang, Wanli Yang, Ulrich Wilhelm Paetzold, Clemens Heske, Lothar Weinhardt
Summary: The impact of BABr surface treatment on double-cation perovskite thin film was studied, revealing modifications in the surface environment which can be crucial for optimizing the treatment and enhancing the performance of perovskite solar cells.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Luyao Wang, Xiaobao Li, Xiangchen Hu, Shuyue Chen, Zhehao Qiu, Yifan Wang, Hui Zhang, Yi Yu, Bo Yang, Yong Yang, Pasquale Orgiani, Carmela Aruta, Nan Yang
Summary: This study investigates the role of grain boundaries in the thermal stability of platinum doped cerium oxide (Pt/CeO2) using in-situ ambient-pressure X-ray photoemission spectroscopy (APXPS). By introducing grain boundaries in Pt/CeO2 thin films, the researchers demonstrate the enhanced stability of Pt2+ ions induced by Ce3+ ions at the grain boundaries. The findings highlight the importance of grain boundaries in the atomic-scale design of thermally stable catalytic active sites.
Article
Engineering, Electrical & Electronic
Sourav Chowdhury, Anupam Jana, Arup Kumar Mandal, Ram Janay Choudhary, Deodatta Moreshwar Phase
Summary: The study investigates the electronic phase switching in thin films of negative Delta materials by controlling key parameters U and Delta, and observing charge disproportionation. It demonstrates the potential of SrCoOx thin films in Mottronic applications through experimental analysis.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Physical
Luyao Wang, Xiaobao Li, Xiangchen Hu, Shuyue Chen, Zhehao Qiu, Yifan Wang, Hui Zhang, Yi Yu, Bo Yang, Yong Yang, Pasquale Orgiani, Carmela Aruta, Nan Yang
Summary: Understanding the role of grain boundaries in the thermal stability of platinum doped cerium oxide (Pt/CeO2) is crucial for designing high-performance catalytic systems. In this study, in-situ ambient-pressure X-ray photoemission spectroscopy (APXPS) was used to investigate the effect of grain boundaries on the stability of Pt/CeO2. The results demonstrate that grain boundaries enhance the stability of Pt2+ ions by providing an ideal coordinated site for anchoring and limiting the formation of oxygen vacancies during the reduction process.
Article
Chemistry, Multidisciplinary
E. Georgopoulou-Kotsaki, P. Pappas, A. Lintzeris, P. Tsipas, S. Fragkos, A. Markou, C. Felser, E. Longo, M. Fanciulli, R. Mantovan, F. Mahfouzi, N. Kioussis, A. Dimoulas
Summary: The 2D van der Waals ferromagnetic metals FexGeTe2 with x = 3-5 have attracted significant attention. In this study, epitaxial Fe5-dGeTe2 (FGT) heterostructures were grown on insulating crystalline substrates using Molecular Beam Epitaxy (MBE). The addition of Bi2Te3 topological insulator (TI) to FGT films significantly enhanced the saturation magnetization and Curie temperature (Tc), with record values of 570 K obtained.
Article
Physics, Multidisciplinary
Daniel S. S. Sanchez, Tyler A. A. Cochran, Ilya Belopolski, Zi-Jia Cheng, Xian P. Yang, Yiyuan Liu, Tao Hou, Xitong Xu, Kaustuv Manna, Chandra Shekhar, Jia-Xin Yin, Horst Borrmann, Alla Chikina, Jonathan D. D. Denlinger, Vladimir N. N. Strocov, Weiwei Xie, Claudia Felser, Shuang Jia, Guoqing Chang, M. Zahid Hasan
Summary: The classification of electronic phases is based on two prominent paradigms: correlations and topology. Electron correlations lead to superconductivity and charge density waves, while the Berry phase gives rise to electronic topology. The combination of these two paradigms has prompted the search for electronic instabilities near the Fermi level of topological materials. This study identifies the electronic topology of chiral fermions as the driving force behind van Hove singularities that host electronic instabilities in the surface band structure.
Article
Physics, Multidisciplinary
Belen E. Zuniga-Cespedes, Kaustuv Manna, Hilary M. L. Noad, Po-Ya Yang, Michael Nicklas, Claudia Felser, Andrew P. Mackenzie, Clifford W. Hicks
Summary: By applying a combination of uniaxial stress and magnetic field, we have observed a significant anomalous Hall effect in a bulk sample of a cubic member of the Mn3X family for the first time. The observed effect remains unchanged when the stress is removed, indicating that it is not induced by stress-induced ferromagnetic moments.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
Tyler A. Cochran, Ilya Belopolski, Kaustuv Manna, Mohammad Yahyavi, Liu Yiyuan, Daniel S. Sanchez, Cheng Zi-Jia, Xian P. Yang, Daniel Multer, Yin Jia-Xin, Horst Borrmann, Alla Chikina, Jonas A. Krieger, Jaime Sanchez-Barriga, Patrick Le Fevre, Francois Bertran, Vladimir N. Strocov, Jonathan D. Denlinger, Chang Tay-Rong, Jia Shuang, Claudia Felser, Hsin Lin, Chang Guoqing, M. Zahid Hasan
Summary: In this Letter, the authors discovered the higher-fold topology of a chiral crystal using a combination of fine-tuned chemical engineering and photoemission spectroscopy. They identified all bulk branches of a higher-fold chiral fermion and revealed a multigap bulk boundary correspondence. This demonstration of multigap electronic topology will drive future research on unconventional topological responses.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Chunyu Guo, A. Alexandradinata, Carsten Putzke, Amelia Estry, Teng Tu, Nitesh Kumar, Feng-Ren Fan, Shengnan Zhang, Quansheng Wu, Oleg V. Yazyev, Kent R. Shirer, Maja D. Bachmann, Hailin Peng, Eric D. Bauer, Filip Ronning, Yan Sun, Chandra Shekhar, Claudia Felser, Philip J. W. Moll
NATURE COMMUNICATIONS
(2023)
Correction
Multidisciplinary Sciences
Yudi Zhang, Kathryn E. Arpino, Qun Yang, Naoki Kikugawa, Dmitry A. Sokolov, Clifford W. Hicks, Jian Liu, Claudia Felser, Guowei Li
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Subhajit Roychowdhury, Mengyu Yao, Kartik Samanta, Seokjin Bae, Dong Chen, Sailong Ju, Arjun Raghavan, Nitesh Kumar, Procopios Constantinou, Satya N. Guin, Nicholas Clark Plumb, Marisa Romanelli, Horst Borrmann, Maia G. Vergniory, Vladimir N. Strocov, Vidya Madhavan, Chandra Shekhar, Claudia Felser
Summary: In this study, the electronic structure of ferromagnetic EuCd2As2, predicted to be an ideal Weyl semimetal, is investigated using angle-resolved photoemission spectroscopy and scanning tunneling microscopy. The experimental results are in close agreement with the first principles calculations. Furthermore, anomalous Hall conductivity and Nernst effect are observed, resulting from the non-zero Berry curvature and the topological Hall effect arising from changes in the band structure caused by spin canting produced by magnetic fields. These findings provide insights into exotic quantum phenomena in inorganic topological materials with multiple pairs of Weyl nodes.
Article
Materials Science, Multidisciplinary
Hua Lv, Edouard Lesne, Rebeca Ibarra, Yan Sun, Anastasios Markou, Claudia Felser
Summary: In this study, the structural, magnetic, and electrical magnetotransport properties of 24 and 51 nm thick B20-RhSi thin films grown by magnetron sputtering were investigated. The films exhibited a nonmagnetic ground state and metallic behavior. It was confirmed that the temperature-dependent electrical resistivity is governed by electron-phonon scattering. The ability to grow textured-epitaxial thin films of nonmagnetic B20 chiral topological semimetals is an important step toward designing chiraltronic devices with novel functionalities.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Luca Tomarchio, Sen Mou, Lorenzo Mosesso, Anastasios Markou, Edouard Lesne, Claudia Felser, Stefano Lupi
Summary: In this paper, we investigate the terahertz emission from thin films of the magnetic topological nodal semimetal Co2MnGa when excited by femtosecond optical pulses. We identify multiple THz generation mechanisms, including a photon-drag effect induced by radiation pressure and a photovoltaic effect from the topological surface states of CMG. This interplay between generation mechanisms highlights the potential of Co2MnGa topological nodal semimetals for THz emitter devices.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Physics, Multidisciplinary
David R. Saykin, Camron Farhang, Erik D. Kountz, Dong Chen, Brenden R. Ortiz, Chandra Shekhar, Claudia Felser, Stephen D. Wilson, Ronny Thomale, Jing Xia, Aharon Kapitulnik
Summary: This study reports high-resolution polar Kerr effect measurements on CsV3Sb5 single crystals to search for evidence of spontaneous time-reversal symmetry breaking below the charge-order transition. Utilizing two different versions of zero-area loop Sagnac interferometers operating at 1550 nm wavelength, the researchers found no observable Kerr effect within the noise floor limit. Simultaneous coherent reflection ratio measurements confirmed the sharpness of the charge-order transition, suggesting that time-reversal symmetry is unlikely to be broken in the charge ordered state in CsV3Sb5.
PHYSICAL REVIEW LETTERS
(2023)
Review
Nanoscience & Nanotechnology
Georgios Varnavides, Amir Yacoby, Claudia Felser, Prineha Narang
Summary: As high-quality single-crystal materials used in electronic devices reach smaller scales, charge-transport phenomena lead to inhomogeneous spatial signatures with significant effects on material properties. These signatures, including spatially varying dissipation and interface resistance, are crucial for device control. This Review examines the inhomogeneous charge flow signatures in conductors, focusing on electron hydrodynamics, where electrons exhibit strong interactions and flow collectively like fluids. Recent experimental advances and theoretical frameworks are discussed, along with new charge-transport phenomena introduced by crystal symmetry in materials.
NATURE REVIEWS MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Irian Sanchez-Ramirez, Maia G. Vergniory, Claudia Felser, Fernando de Juan
Summary: Among the quasi-one-dimensional transition metal tetrachalcogenides (MSe4)nI (M = Nb,Ta), the n = 3 compounds exhibit structural transitions with puzzling transport behavior instead of charge density waves. Recent discovery of a metallic polytype of (TaSe4)3I with coexisting ferromagnetism and superconductivity at low temperature challenges previous reports. In this study, ab initio and tight-binding band-structure calculations are used to explain the observed transport gaps and clarify the controversy regarding ARPES and optical conductivity experiments. The effect of small extrinsic hole doping and its implications for magnetism and superconductivity are also discussed.
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
Eleanor F. Scott, Katherine A. Schlaak, Poulomi Chakraborty, Chenguang Fu, Satya N. Guin, Safa Khodabakhsh, Ashley E. Paz Y. Puente, Claudia Felser, Brian Skinner, Sarah J. Watzman
Summary: In this study, it was discovered that polycrystalline NbP exhibits a large Nernst effect and a large magneto-Seebeck effect simultaneously, which is rarely observed in a single material at the same temperature. Through doping, the temperature dependence of these magnetothermoelectric effects can be altered, providing a potential tuning mechanism for device applications.
Article
Engineering, Electrical & Electronic
Ryotaro Okabe, Mingda Li, Yuma Iwasaki, Nicolas Regnault, Claudia Felser, Masafumi Shirai, Alexander Kovacs, Thomas Schrefl, Atsufumi Hirohata
Summary: This letter summarizes the recent development of using artificial intelligence and machine learning in the search for magnetic materials, and briefly introduces the approaches used in materials discovery. The authors also provide a flowchart to assist in selecting the appropriate methods for material search. The letter also covers the authors' recent research activities in magnetism and quantum materials.
IEEE MAGNETICS LETTERS
(2023)