Article
Chemistry, Physical
Yangmu Li, Nader Zaki, Vasile O. Garlea, Andrei T. Savici, David Fobes, Zhijun Xu, Fernando Camino, Cedomir Petrovic, Genda Gu, Peter D. Johnson, John M. Tranquada, Igor A. Zaliznyak
Summary: The electronic properties of Fe1+yTe1-xSex show significant compositional dependence, with unique electronic characteristics observed only within specific ranges of Fe and Te concentrations. FeTe0.55Se0.45 is located near the phase boundaries of superconducting and topological states, leading to its inhomogeneity.
Article
Multidisciplinary Sciences
Thuc T. Mai, Kevin F. Garrity, Amber McCreary, Joshua Argo, Jeffrey R. Simpson, Vicky Doan-Nguyen, Rolando Valdes Aguilar, Angela R. Hight Walker
Summary: Magnetic excitations in van der Waals materials, particularly in the 2D limit, have been studied using temperature-dependent magnetoRaman spectroscopy. The researchers identified hybridization of two-magnon excitations with two phonons in manganese phosphorus triselenide, and constructed a model to explain the observations. This work demonstrates the strong hybridization between phonons and a two-magnon continuum, providing insight into interactions in 2D magnetic materials.
Article
Physics, Multidisciplinary
Qianni Jiang, Yue Shi, Morten H. Christensen, Joshua J. Sanchez, Bevin Huang, Zhong Lin, Zhaoyu Liu, Paul Malinowski, Xiaodong Xu, Rafael M. Fernandes, Jiun-Haw Chu
Summary: In this study, the authors investigate the nematic susceptibility and its relationship with spin fluctuations in Fe1+yTe1-xSex using elastoresistivity measurement. They find that the nematic fluctuations in two symmetry channels are closely linked to the corresponding spin fluctuations, and observe an unusual temperature dependence of the nematic susceptibility attributed to the loss of coherence of the d(xy) orbital. The research highlights the importance of orbital differentiation on the nematic properties of iron-based materials.
COMMUNICATIONS PHYSICS
(2023)
Article
Physics, Multidisciplinary
Emil Vinas Bostroem, Tahereh Sadat Parvini, James W. McIver, Angel Rubio, Silvia Viola Kusminskiy, Michael A. Sentef
Summary: Controlling edge states of topological magnon insulators is a promising route to stable spintronics devices. However, experimentally determining the topology of magnon bands is challenging. In this study, we establish a fundamental relationship between light-matter coupling and the quantum geometry of magnon states. We propose the use of two-magnon Raman circular dichroism as an optical probe of magnon topology in honeycomb magnets, including the Chern number and topological gap. Our findings open up possibilities for integrating light and topological magnons in functional quantum devices.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Yanxing Yang, Hewei Zhang, Haizheng Zhuang
Summary: This study reports on the measurement and analysis of phonon anomalies in iron-based superconductors, revealing their existence and dependence, and suggesting a possible common mechanism.
Article
Physics, Multidisciplinary
Sheng Liu, Andres Granados del Aguila, Dhiman Bhowmick, Chee Kwan Gan, T. Thu Ha Do, M. A. Prosnikov, David Sedmidubsky, Zdenek Sofer, Peter C. M. Christianen, Pinaki Sengupta, Qihua Xiong
Summary: In FePS3, strong coupling between magnons and phonons was directly observed using magneto-Raman spectroscopy at magnetic fields up to 30 Tesla. A hybridized magnon-phonon quasiparticle formed due to field-driven resonance with a nearby phonon mode. The polarized Raman results demonstrated the transfer of spin angular momentum from magnons to phonons, generating phonon spin through strong coupling.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
M. A. Prosnikov
Summary: The study presented the linear spin-wave theory of PbFeBO4 spin dynamics, showing that the observed magnetic excitations in Raman scattering experiments are optical magnon and two-magnon modes. The results suggest a negligible role of magnon-magnon interactions, with only a small deviation in the two-magnon band from the one-magnon density of states.
Review
Chemistry, Physical
Jia-Min Lai, Ya-Ru Xie, Jun Zhang
Summary: Electron-phonon coupling significantly impacts the properties of 2D materials, with inelastic light scattering serving as a powerful experimental tool. This review provides an overview of the basic theory and experimental advances in detecting electron-phonon coupling in 2D materials through Raman and Brillouin scattering techniques.
Article
Physics, Applied
Chandra P. Neupane, Jeremy Sylvester, Xianghan Xu, Sang-Wook Cheong, Feruz Ganikhanov
Summary: Time-domain coherent Raman techniques were used to selectively measure the ultrafast decay rates of optical phonons in cubic BaSnO3 perovskite. The damping rates of the phonon modes were found to be within 1.27-1.59 ps(-1) at room temperature, with Raman linewidths within 6.7-8.4 cm(-1). The study of phonon decay mechanisms is crucial for understanding the limiting factors in achieving high carrier mobility in device applications of the material.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Multidisciplinary
Dongjin Oh, Dongjoon Song, Younsik Kim, Shigeki Miyasaka, Setsuko Tajima, Jin Mo Bok, Yunkyu Bang, Seung Ryong Park, Changyoung Kim
Summary: The study reveals that at temperature T-B1g, the B-1g phonon softens due to the formation of an energy gap on the Fermi surface induced by a charge density wave order. This demonstrates a method to investigate Fermi surface instabilities above the superconducting transition temperature through phonon Raman studies.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Anudeepa Ghosh, Mainak Palit, Sujan Maity, Vivek Dwij, Sumesh Rana, Subhadeep Datta
Summary: Temperature-dependent Raman spectroscopic studies on FePS3 reveal spin-phonon coupling, spin ordering, and magnon excitation phenomena as temperature decreases. Raman spectroscopy can predict the magnetic transition temperature of magnetic insulators and track magnon transport in heterostructures involving different electronic and magnetic orderings.
Article
Materials Science, Multidisciplinary
K. A. Smith, S. P. Ramkumar, N. C. Harms, A. J. Clune, S-W Cheong, Z. Liu, E. A. Nowadnick, J. L. Musfeldt
Summary: This study investigated the pressure-driven phase transition in multiferroic h-Lu0.6Sc0.4FeO3 using a combination of techniques, including diamond anvil cell techniques, synchrotron-based infrared and Raman scattering spectroscopies, symmetry analysis, and lattice dynamics calculations. The comparison of measured and predicted phonon patterns revealed a structural transition at 15 GPa. The symmetry breaking across the polar -> antipolar transition was found to be analogous to other materials with strain-driven and temperature-induced transitions.
Article
Physics, Applied
L. D. Espinosa-Cuellar, L. F. Lastras-Martinez, R. E. Balderas-Navarro, R. Castro-Garcia, A. Lastras-Martinez, J. M. Flores-Camacho, Mohammad Esmail Aryaee Panah, Elizaveta Semenova, Andrei V. Lavrinenko
Summary: This study examines the spatial modulation of TO mode amplitudes in highly doped InP semiconductors using a grating. By exciting the sample with linearly polarized light parallel and perpendicular to the grating grooves, a change in the amplitude of phonon optical response for the TO mode is observed.
APPLIED PHYSICS LETTERS
(2021)
Article
Spectroscopy
Anoop Sunny, Karthikeyan Balasubramanian
Summary: In this study, the phonon, magnon, and magnetic properties of copper-doped nanocrystalline nickel(II) oxide were extensively studied using room-temperature Raman spectroscopy. The observed deviations in the wavenumbers of phonon modes from theoretical predictions were attributed to the phonon-magnon interaction. The variations in magnon excitations with the concentration of Cu doping were investigated and the suppression and blue shifting of the two-magnon excitations indicated changes in the magnetic behavior. The modifications in the antiferromagnetic nature and the formation of multiphase magnetic properties were investigated using a vibrating sample magnetometer.
JOURNAL OF RAMAN SPECTROSCOPY
(2022)
Article
Physics, Applied
Weijun Ren, Jie Chen, Gang Zhang
Summary: This paper reviews the impact of twisted angle on the phonon properties and discusses the research on phonon transport behavior. It also addresses the unresolved questions and challenges in the phonon characteristics of twisted two-dimensional materials and proposes possible solutions.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Multidisciplinary
Hao Jin, Alessandro Narduzzo, Minoru Nohara, Hidenori Takagi, N. E. Hussey, Kamran Behnia
Summary: In this study, the thermoelectric response in heavily overdoped, non-superconducting La1.67Sr0.33CuO4 was investigated. Despite the electron-like curvature of the Fermi surface, the positive Seebeck coefficient at low temperatures was observed, which is attributed to the non-trivial energy dependence of the scattering time. It is argued that this feature implies a strong electron-hole asymmetry, hindering the formation of Cooper pairs in the superconducting ground state at lower doping levels.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2021)
Article
Allergy
Tomonori Endo, Daiya Asaka, Tsuguhisa Nakayama, Shota Saito, Hiroki Kodama, Ryoto Mitsuyoshi, Naoki Sugimoto, Sachiko Omae, Hidenori Takagi, Yuhya Wakasa, Kenjirou Ozawa, Makoto Takano, Fumio Takaiwa, Hiromi Kojima, Saburo Saito
Summary: The study demonstrated that low-dose oral administration of transgenic rice containing human T-cell epitopes from Japanese cedar pollen allergens reduced allergen-specific T-cell responses and improved medication scores in the second season of administration. Further research is needed to confirm the effectiveness of this approach.
ALLERGY AND ASTHMA PROCEEDINGS
(2021)
Article
Multidisciplinary Sciences
Qisi Wang, Karin von Arx, Masafumi Horio, Deepak John Mukkattukavil, Julia Kuspert, Yasmine Sassa, Thorsten Schmitt, Abhishek Nag, Sunseng Pyon, Tomohiro Takayama, Hidenori Takagi, Mirian Garcia-Fernandez, Ke-Jin Zhou, Johan Chang
Summary: Charge order is universal in all hole-doped cuprates, with electron-electron interactions believed to be essential and electron-phonon interactions playing a significant role as well, especially around the charge ordering wave vector. The study reveals phonon softening and lifetime shortening near the charge ordering wave vector and an enhancement of electron-phonon coupling upon cooling into the low-temperature tetragonal phase, suggesting that electron-phonon coupling substantially contributes to the emergence of long-range charge-stripe order in cuprates along with electronic correlations.
Article
Materials Science, Multidisciplinary
Mohamed Oudah, Minu Kim, Ksenia S. Rabinovich, Kateryna Foyevtsova, Graham McNally, Berkay Kilic, Kathrin Kuester, Robert Green, Alexander Boris, George Sawatzky, Andreas P. Schnyder, D. A. Bonn, Bernhard Keimer, Hidenori Takagi
Summary: In this study, it was found that Ag2BiO3 exhibits a bond disproportionated state with holes on the oxygen atoms, supporting the presence of two different bismuth states through X-ray photoelectron spectroscopy results. The compound has an estimated band gap of approximately 1.25 eV and is expected to host Weyl nodal chains in its band structure. Additionally, similarities were highlighted between Ag2BiO3 and the well-known disproportionated bismuthate BaBiO3, with both compounds showing importance of hybridization of Bi 6s and O 2p atomic orbitals in shaping the band structure.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Multidisciplinary
Dilip Bhoi, Jun Gouchi, Naoka Hiraoka, Yufeng Zhang, Norio Ogita, Takumi Hasegawa, Kentaro Kitagawa, Hidenori Takagi, Kee Hoon Kim, Yoshiya Uwatoko
Summary: This study shows a continuous tuning of magnetic and electrical properties of a CrGeTe3 single crystal using pressure, resulting in a transition from a ferromagnetic insulator to a correlated 2D Fermi metal. The absence of an accompanying structural distortion across the insulator-metal transition suggests that the pressure induced modification of electronic ground states is driven by electronic correlation, providing a rare example of bandwidth-controlled insulator-metal transition in a vdW material.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Mari Watanabe, Takeshi Suzuki, Takashi Someya, Yu Ogawa, Shoya Michimae, Masami Fujisawa, Teruto Kanai, Jiro Itatani, Tomohiko Saitoh, Shik Shin, Kozo Okazaki
Summary: We investigated the nonequilibrium electronic structure of 2H-NbSe2 using time-and angle-resolved photoemission spectroscopy. We found that strong photo-excitation distinctly modulates the band structure, allowing for control of the functionalities of solid-state materials.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Physics, Multidisciplinary
Takumi Mitsuoka, Yu Takahashi, Takeshi Suzuki, Mario Okawa, Hidenori Takagi, Naoyuki Katayama, Hiroshi Sawa, Minoru Nohara, Mari Watanabe, Jiadi Xu, Qianhui Ren, Masami Fujisawa, Teruto Kanai, Jiro Itatani, Kozo Okazaki, Shik Shin, Takashi Mizokawa
Summary: The photoinduced semimetal phase of Ta2Ni1-xCoxSe5 (x = 0.0 and 0.1) was studied using time-resolved angle-resolved photoemission spectroscopy. The observed band dispersions roughly agree with the generalized gradient approximation (GGA) calculation, but fail to reproduce the band gap at ambient conditions. This suggests that the electron-hole interaction, not properly included in GGA, is screened out by the photoexcited carriers. No indication of pseudogap was found. The conduction and valence bands exhibit quasi one-dimensional Fermi surfaces with similar momentum positions, indicating a quasi one-dimensional line-node semimetal.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Multidisciplinary
Xian P. Yang, Yigui Zhong, Sougata Mardanya, Tyler A. Cochran, Ramakanta Chapai, Akifumi Mine, Junyi Zhang, Jaime Sanchez-Barriga, Zi-Jia Cheng, Oliver J. Clark, Jia-Xin Yin, Joann Blawaf, Guangming Cheng, Ilya Belopolski, Tsubaki Nagashima, Sahand Najafzadeh, Shiyuan Gao, Nan Yao, Arun Basrasil, Rongying Jin, Tay-Ron Chang, Shik Shin, Kozo Okazaki, M. Zahid Hasan
Summary: We investigate the momentum dependence of the superconducting gap distribution in the Dirac material PdTe, and find that it is a spin-orbit coupled Dirac semimetal with a topological Fermi arc. The surface state of PdTe exhibits a fully gapped superconducting Cooper pairing structure below Tc (approximately 4.5 K), while a node is observed in the bulk near the Brillouin zone boundary, away from the topological Fermi arc. These observations demonstrate the band resolved electronic correlation between topological Fermi arc states and their role in Cooper pairing, as well as the coexistence of nodeless and nodal gap structures enforced by spin-orbit coupling in PdTe.
PHYSICAL REVIEW LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Mario Okawa, Yuka Akabane, Mizuki Maeda, Gangjian Tan, Li-Dong Zhao, Mercouri G. Kanatzidis, Takeshi Suzuki, Mari Watanabe, Jiadi Xu, Qianhui Ren, Masami Fujisawa, Teruto Kanai, Jiro Itatani, Shik Shin, Kozo Okazaki, Naurang L. Saini, Takashi Mizokawa
Summary: In this study, we used time- and angle-resolved photoemission spectroscopy to investigate SnSe and found its potential for high thermoelectric performance and anisotropy.
SCRIPTA MATERIALIA
(2023)
Article
Physics, Applied
Qianhui Ren, Takeshi Suzuki, Teruto Kanai, Jiro Itatani, Shik Shin, Kozo Okazaki
Summary: We studied the nonequilibrium electronic structure of 1T-TaS2 using time- and angle-resolved photoemission spectroscopy. Strong photoexcitation leads to the collapse of the Mott gap and induces a photo-induced metallic phase. The oscillation of photoemission intensity is found to be caused by coherent phonons corresponding to the amplitude mode of the charge density wave. By analyzing the frequency-domain angle-resolved photoemission spectroscopy, we observe anti-phase oscillation between two peak structures, which are attributed to the minimum and maximum band positions in energy synchronizing with the CDW amplitude mode.
APPLIED PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Yigui Zhong, Shaozhi Li, Hongxiong Liu, Yuyang Dong, Kohei Aido, Yosuke Arai, Haoxiang Li, Weilu Zhang, Youguo Shi, Ziqiang Wang, Shik Shin, H. N. Lee, H. Miao, Takeshi Kondo, Kozo Okazaki
Summary: In the study, it was found that the new kagome metal CsV3Sb5 may have superconductivity that intertwines with time-reversal and spatial symmetry-breaking orders, suggesting an unconventional pairing mechanism. Through angle-resolved photoemission spectroscopy and Eliashberg function analysis, an EPC strength of lambda=0.45-0.6 for both Sb 5p and V 3d electronic bands was determined, supporting the conventional superconducting transition temperature in CsV3Sb5. Additionally, the EPC on the V 3d-band was enhanced to lambda~0.75 as the superconducting transition temperature elevated to 4.4 K in Cs(V0.93Nb0.07)(3)Sb-5. These results provide important insights into the pairing mechanism in the kagome superconductor CsV3Sb5.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Y. Zhao, T. Suzuki, T. Iimori, H-W Kim, J. R. Ahn, M. Horio, Y. Sato, Y. Fukaya, T. Kanai, K. Okazaki, S. Shin, S. Tanaka, F. Komori, H. Fukidome, I Matsuda
Summary: The carrier dynamics in various types of epitaxial graphene layers on SiC substrates were studied using TARPES. Layer-dependent electron doping was observed in the Dirac bands of quasicrystalline bilayer graphene, resulting in the generation of transient voltage between the upper and lower layers. The amount of photoinduced carrier transport depends on the distance from the substrate. Comparison of TARPES results between flat and stepped SiC substrates suggests that the doping carriers likely originate from interface step states.
Article
Physics, Multidisciplinary
D. Huang, H. Nakamura, H. Takagi
Summary: The planar Hall effect has recently attracted attention in a wide range of topological metals and insulators, including antiperovskites. Unusual sixfold oscillations were observed in Sr3SnO, indicating a richer interplay of microscopic processes in this material.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Materials Science, Multidisciplinary
S. Suetsugu, K. Kitagawa, T. Kariyado, A. W. Rost, J. Nuss, C. Muhle, M. Ogata, H. Takagi
Summary: In this study, Pb-207 NMR measurements were conducted to explore the microscopic origin of diamagnetism in Sr3PbO, a three-dimensional Dirac electron system. The results successfully separated the spin and orbital components in the Knight shift K, establishing that the enhanced diamagnetism originates from the orbital contribution of Dirac electrons, consistent with the theory of giant orbital diamagnetism.
Article
Materials Science, Multidisciplinary
Takeshi Suzuki, Yasushi Shinohara, Yangfan Lu, Mari Watanabe, Jiadi Xu, Kenichi L. Ishikawa, Hide Takagi, Minoru Nohara, Naoyuki Katayama, Hiroshi Sawa, Masami Fujisawa, Teruto Kanai, Jiro Itatani, Takashi Mizokawa, Shik Shin, Kozo Okazaki
Summary: Researchers used the FDARPES technique to discover that in the photoinduced insulator-to-metal transition of Ta2NiSe5, the lattice modulation induced by the 2 THz phonon mode is the most relevant for the emergence of the photoinduced semimetallic state. Additionally, in the transient state, both semimetallic and semiconducting bands coexist, and FDARPES spectra can selectively detect the phonon-specific couplings to these coexistent band structures by resolving them in the frequency domain.
