Article
Chemistry, Physical
Huiying Gao, Menglei Li, Yu Yang, Ping Zhang
Summary: First-principles calculations were used to study the structural, magnetic, and electronic properties of PuO2-xHx compounds in fluorite structure. Different density functional methods were applied to investigate the unique characteristics of the materials under various oxygen and hydrogen compositions. The results showed distinct lattice deformation and magnetic behaviors depending on the Pu and H content, with a transition from insulator to metal property observed within a specific range of x value.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Multidisciplinary Sciences
Joanna Stepien, Damian Rybicki, Marcin Sikora, Zbigniew Bukowski, Michal Babij, Lukasz Gondek, Czeslaw Kapusta, Tomasz Straczek, Kamil Goc, Danilo Oliveira De Souza
Summary: Superconductivity in high-temperature superconductors is achieved through doping, either by hole or electron doping. Understanding the effects of doping on the properties of these materials is of great interest. X-ray absorption spectroscopy measurements on electron doped compounds from the 112 and 122 families of iron pnictides showed electron charge redistribution between As and Fe. The results suggest that doped charges are localized on the dopant site, but do not explain the absence of superconductivity in the case of Ni doping in the 122 family.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Yu Wang, Zhigang Song, Jiawei Wan, Sophia Betzler, Yujun Xie, Colin Ophus, Karen C. Bustillo, Peter Ercius, Lin-Wang Wang, Haimei Zheng
Summary: This study presents a new method for synthesizing moire superlattices with strong chemical bonding, using lead sulfide as an example. Water-soluble ligands are used as a removable template to obtain ultrathin PbS nanosheets, which are then assembled into direct-contact bilayers with various twist angles. Atomic-resolution imaging reveals periodic structural reconstruction at the superlattice interface due to the strong metavalent coupling. The twist-angle-dependent electronic structure, particularly the emergence of separated flat bands, is demonstrated through electron energy loss spectroscopy and theoretical calculations. The localized states of flat bands resemble well-arranged quantum dots, suggesting potential applications in devices.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Ya-Le Tao, Wei Zeng, Juan Gao, Zheng-Tang Liu, Zhen Jiao, Qi-Jun Liu
Summary: This study systematically investigates the property changes and metallization mechanism of alkaline earth metal hydrides based on first-principles calculations. It is found that external pressure can induce structural phase transitions and decrease or close the bandgap of these hydrides. The formation of hydrogen units accelerates the metallization process and promotes the realization of high superconducting transition temperature. The theoretical findings suggest that MgH4-I4/mmm has the potential to be a high-temperature superconductor and provide new ideas for the search of unknown high-temperature superconducting materials.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Ya-Le Tao, Wei Zeng, Juan Gao, Zheng-Tang Liu, Zhen Jiao, Qi-Jun Liu
Summary: The metallization of alkaline earth metal hydrides offers a path towards achieving near-room temperature superconductivity. Through first-principles calculations, we investigate the properties and the metallization mechanisms of dihydrides and tetrahydrides of alkaline earth metals. Under applied pressure, the structures of these hydrides undergo phase transitions, and the size of the bandgap decreases until it eventually closes. Our findings suggest that MgH4-I4/mmm has the potential to be a high-temperature superconductor and provide new ideas for the search of unknown high-temperature superconducting materials.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Shaowen Xu, Fanhao Jia, Shunbo Hu, Athinarayanan Sundaresan, Nikita Ter-Oganessian, Alexander P. Pyatakov, Jinrong Cheng, Jincang Zhang, Shixun Cao, Wei Ren
Summary: Density functional theory calculations were used to predict the properties of few-atomic-layer oxides based on polar perovskite KTaO3, revealing varying semiconductor and half-metal behaviors in systems with different numbers of atomic layers, with thicker systems exhibiting ferromagnetic surface states.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Grace P. Chen, Elena Bykova, Maxim Bykov, Eric Edmund, Zi-Yu Cao, Xiao-Jia Chen, Jesse S. Smith, Stella Chariton, Vitali B. Prakapenka, Alexander F. Goncharov
Summary: The high-pressure properties of layered transition metal dichalcogenide 2H-NbSe2 were investigated, revealing its structural stability up to 35 GPa. The lattice compressibility changes from anisotropic to isotropic with increasing pressure. The compression behavior of interatomic bonds is highly anisotropic, while the intramolecular bonds show a nonmonotonic pressure dependence with a maximum at -12 GPa.
Article
Materials Science, Multidisciplinary
Xiaomeng Wang, Tong Chen, Beatriz H. Cogollo-Olivo, Chi Ding, Tianheng Huang, Qing Lu, Jian Sun
Summary: By utilizing crystal structural search and ab initio calculations, pressure-induced structural and electronic phase transitions were observed in the semiconductor indium tellurium iodine (InTeI). The study found that the ambient P2(1)/c phase of InTeI transforms into a tetragonal P4/nmm-I phase under high pressure, exhibiting metallization and superconductivity with T-c around 7 K. Furthermore, atomic substitution, such as replacing iodine atoms with lighter chlorine atoms, can further increase the superconducting temperature T-c of InTeI to around 9.7 K in the P4/nmm-I phase.
Article
Chemistry, Inorganic & Nuclear
Hong-Xiong Liu, Jun Li, Shan-Shan Miao, Hai L. Feng, Jian-Qi Li, You-Guo Shi
Summary: Single crystals and polycrystalline samples of Ho5Pd4Sn12 were synthesized using different methods. The crystal structure of Ho5Pd4Sn12 was found to be tetragonal at room temperature and monoclinic below -194 K. This structural transition was confirmed by transmission electron microscopy and specific heat data.
INORGANIC CHEMISTRY
(2022)
Article
Materials Science, Multidisciplinary
M. G. Kim, W. Ratcliff, D. M. Pajerowski, J-W Kim, J-Q Yan, J. W. Lynn, A. Goldman, A. Kreyssig
Summary: The magnetic ordering and structural distortion in PrFeAsO crystals, the basis compound for oxypnictide superconductors, were studied using high-resolution x-ray diffraction, neutron diffraction, and x-ray resonant magnetic scattering. The results revealed the tetragonal-to-orthorhombic phase transition, antiferromagnetic phase transitions of Fe and Pr moments at specific temperatures. The magnetic moments of Pr were found to align along the longer orthorhombic axis and order antiferromagnetically along the a axis, while showing ferromagnetic ordering along the b and c directions, indicating no reorientation of moments.
Article
Multidisciplinary Sciences
Zheng Ren, Hong Li, He Zhao, Shrinkhala Sharma, Ziqiang Wang, Ilija Zeljkovic
Summary: Using strain-engineered FeSe thin films, we discovered a local decoupling of electron nematicity and structural anisotropy, indicating stiffness of the nematic order parameter at the nanoscale, which contrasts with previous observations in Fe-based superconductors.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Yuanyuan Yang, Qisi Wang, Shaofeng Duan, Hongliang Wo, Chaozhi Huang, Shichong Wang, Lingxiao Gu, Dao Xiang, Dong Qian, Jun Zhao, Wentao Zhang
Summary: In this study, high-resolution time- and angle-resolved photoemission measurements were conducted on FeSe superconductors. Two critical excitation fluences corresponding to ultrafast electronic phase transitions were discovered. The importance of two equilibrium electronic phase transitions and the contribution of the structural transition in FeSe were determined.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Xinyou Liu, Wei Zhang, Kwing To Lai, K. Moriyama, J. L. Tallon, K. Yoshimura, Swee K. Goh
Summary: (CaxSr1-x)(3)Rh4Sn13 is a rare system that shows an interesting interplay between structural quantum criticality and superconductivity. By studying the critical current density, it has been found that the critical current density at zero temperature is significantly enhanced near the structural quantum critical point.
Article
Physics, Multidisciplinary
Shiyu Deng, Siyu Chen, Bartomeu Monserrat, Emilio Artacho, Siddharth S. Saxena
Summary: FePS3 is a prototype van der Waals layered antiferromagnet and Mott insulator that undergoes a pressure-induced dimensionality crossover and insulator-to-metal transition. These transitions result in the emergence of a novel magnetic metallic state. Through computational study, we aim to understand the coexistence of different phases under varying pressures and propose a novel high-pressure phase with distinctive dimensionality and potential origins of metallicity.
Article
Physics, Applied
Jack T. Eckstein, Ekhard K. H. Salje, Christopher J. Howard, Michael A. Carpenter
Summary: The lattice parameter data of WO3 have been analyzed to study the strain variations and phase transitions. The strain/order parameter coupling reveals the character of each phase transition and provides insights into the strain gradients across different ferroelastic phases. The study also explores the relationship between strain and electronic effects, as well as the electronic properties of domain walls in WO3. Understanding these properties is crucial for potential applications in nanoelectronics and neuromorphic computing.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Y-M Kim, K. H. Lee, L. Fu, M-W Oh, S-H Yang, S. Ning, G. Han, M. Y. Kim, J-S Kim, M. Jeong, J. Jang, E. Lee, E. Okunishi, H. Sawada, S- Kim, S. J. Pennycook, Y. H. Lee, S. W. Kim
Summary: Using advanced X-ray spectroscopy, excess Cu doping behavior in ternary Bi2Te2.7Se0.3 bulk alloy is visualized with unprecedented detectability. The study sheds light on the influence of Cu dopants on the properties of materials, potentially impacting the understanding of quantum phenomena in doped nanomaterials and doped topological insulators.
MATERIALS TODAY PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Seung Yong Lee, Joonho Bang, Hyun Yong Song, Byung Il Yoo, Yeongkwan Kim, Kimoon Lee, Dinesh Thapa, Seong-Gon Kim, Sung Wng Kim
Summary: Researchers have reported a new two-dimensional mixed-cation [YGdC]2+·2e- electride, showing ferrimagnetic nature. The ferrimagnetic property is driven by the direct exchange interaction of magnetic interstitial electrons.
NPJ QUANTUM MATERIALS
(2021)
Review
Chemistry, Multidisciplinary
Minyoung Kim, Sang-il Kim, Sung Wng Kim, Hyun-Sik Kim, Kyu Hyoung Lee
Summary: This study investigates the important parameters affecting the conversion efficiency of thermoelectric materials, finding that the weighted mobility ratio can affect the zT value. It suggests that controlling this parameter is a promising way to enhance the zT value of narrow bandgap thermoelectric materials.
ADVANCED MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Liangwei Fu, Kyu Hyoung Lee, Sang-Il Kim, Jae-Hong Lim, Wooseon Choi, Yudong Cheng, Min-Wook Oh, Young-Min Kim, Sung Wng Kim
Summary: Nanostructuring is a common method to enhance the thermoelectric properties of materials, but nanostructured bismuth antimony telluride alloys often suffer from carrier mobility degradation at interfaces. This study shows a new approach by introducing intrinsic Sb-rich precipitates in Bi0.5Sb1.5Te3 alloys to enhance phonon scattering and modulate carrier transport simultaneously. Experimental and theoretical analysis reveals that the optimized sample exhibits outstanding thermoelectric performance at high temperatures.
Article
Chemistry, Multidisciplinary
Se Hwang Kang, Dinesh Thapa, Binod Regmi, Siyuan Ren, Young-Min Kim, Seong-Gon Kim, Sung Wng Kim
Summary: In this study, transition metal-rich monochalcogenides are identified as a new class of low-dimensional electrides with excellent chemical and thermal stability. New two-dimensional electrides are predicted and room-temperature stable electrides have been successfully synthesized. The role of anionic electrons in determining the physical properties of these electrides is also discussed.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Athira Thacharon, Woo-Sung Jang, Jihyun Kim, Joohoon Kang, Young-Min Kim, Sung Wng Kim
Summary: This study reports a rational approach for non-oxidized bare metal nanoparticles (MeNPs) in air without additional surface passivation treatment. It was found that the synthesized bare MeNPs are ultra-stable in ambient air and exhibit no trace of metal oxides even on their outermost atomic layer. This unique resistance to oxidation is attributed to the accumulation of excess electrons on the surface of bare MeNPs.
Article
Multidisciplinary Sciences
Christopher John Butler, Yuhki Kohsaka, Youichi Yamakawa, Mohammad Saeed Bahramy, Seiichiro Onari, Hiroshi Kontani, Tetsuo Hanaguri, Shinichi Shamoto
Summary: In BaNiS2, correlated-electron behavior, namely electronic nematicity, has been observed using scanning tunneling microscopy. The striped patterns in real space are believed to stem from a lifting of degeneracy among electron pockets at the Brillouin zone boundary. A momentum-dependent energy shift with d-form factor suggests an unusual mechanism driving the nematic instability, which is different from conventional Fermi surface perturbations.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Kazuki Iida, Katsuaki Kodama, Yasuhiro Inamura, Mitsutaka Nakamura, Lieh-Jeng Chang, Shin-ichi Shamoto
Summary: In this study, the spin excitation of an ilmenite FeTiO3 powder sample is measured using time-of-flight inelastic neutron scattering. The dynamic magnetic pair-density function D-M(r, E) is obtained from the dynamic magnetic structure factor S-M(Q, E) by Fourier transformation. The real space spin dynamics exhibit magnon mode transitions in the spin-spin correlation with increasing energy, which is well reproduced by simulation using reciprocal space magnon dispersions. This analysis provides a novel opportunity to study the local spin dynamics of various magnetic systems.
SCIENTIFIC REPORTS
(2022)
Article
Multidisciplinary Sciences
Byung Cheol Park, Taewoo Ha, Kyung Ik Sim, Taek Sun Jung, Jae Hoon Kim, Yeongkwan Kim, Young Hee Lee, Teun-Teun Kim, Sung Wng Kim
Summary: This study reports the real-space imaging and control of Jchiral in the topological Dirac semimetal KZnBi at room temperature using near-field terahertz spectroscopy, and observes its spatial flow and temporal dynamics, revealing its ultralong transport length.
Article
Chemistry, Physical
Xinbin Yu, Jisue Moon, Yongqiang Cheng, Luke Daemen, Jue Liu, Sung Wng Kim, Abinash Kumar, Miaofang Chi, Victor Fung, Anibal J. Ramirez-Cuesta, Zili Wu
Summary: NH3 synthesis is a critical industrial process. Ru catalysts have high activity in this reaction but are susceptible to hydrogen poisoning. By using supports like electrides and hydrides, the problem of hydrogen poisoning can be alleviated. However, there is limited research on the structural dynamics of Ru/electride catalysts during the reaction.
CHEMISTRY OF MATERIALS
(2023)
Article
Multidisciplinary Sciences
Seung Yong Lee, Dong Cheol Lim, Md Salman Khan, Jeong Yun Hwang, Hyung Sub Kim, Kyu Hyung Lee, Sung Wng Kim
Summary: The reversible structural and magnetic transitions in electrides can be achieved by substituting quasi-atomic magnetic anionic electrons and non-magnetic hydrogen anions, enabling quantum manipulation of floating electron phases on the electride surface.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Shin-ichi Shamoto, Hiroki Yamauchi, Kazuki Iida, Kazuhiko Ikeuchi, Amelia Elisabeth Hall, Yu-Sheng Chen, Min Kai Lee, Geetha Balakrishnan, Lieh-Jeng Chang
Summary: Local spin correlation orders, including partial order, cooperative paramagnetism, and soliton spin liquid, emerge in the paramagnetic state of the noncentrosymmetric intermetallic antiferromagnet Mn3RhSi. The study reveals that the local spin correlation order in Mn3RhSi has a spiral structure. The possible origins of magnetic cluster formation are discussed in relation to the Lifshitz invariant and the Griffiths phase, and compared with other materials.
COMMUNICATIONS PHYSICS
(2023)
Article
Physics, Multidisciplinary
Qi Sheng, Tatsuya Kaneko, Kohtaro Yamakawa, Zurab Guguchia, Zizhou Gong, Guoqiang Zhao, Guangyang Dai, Changqing Jin, Shengli Guo, Licheng Fu, Yilun Gu, Fanlong Ning, Yipeng Cai, Kenji M. Kojima, James Beare, Graeme M. Luke, Shigeki Miyasaka, Masato Matsuura, Shin-ichi Shamoto, Takashi Ito, Wataru Higemoto, Andrea Gauzzi, Yannik Klein, Yasutomo J. Uemura
Summary: In this study, the properties of the NiS2-xSex system were investigated and it was found that it exhibits a bandwidth controlled Mott transition via (S,Se) substitutions. The experimental results demonstrate significant spin correlations in the AFM region, while the percolation of the conducting paths generated by Ni-Se-Ni bonds leads to the charge transition from AFI to AFM. By comparing Muon and neutron results, an interpenetrating charge and spin percolation model is proposed to explain the behavior of the experimental results.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
Shin-ichi Shamoto, Mitsuhiro Akatsu, Masato Matsuura, Seiko Ohira-Kawamura, Kazuya Harii, Masao Ono, Lieh-Jeng Chang, Takashi U. Ito, Yuichi Nemoto, Jun'ichi Ieda
Summary: The effect of ultrasound injection on the magnetic Bragg peak of yttrium iron garnet has been studied. The magnetic Bragg peak is greatly enhanced with decreasing temperature, and the energy width increases proportionally to the square root of the sample temperature increase induced by the ultrasound injection. Based on a liquid model, the estimated effective mass becomes lighter when magnetic domain walls are removed under a magnetic field. The enhancement of the magnetic Bragg peak is closely related to the spin-lattice coupling.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
K. Hagiwara, M. Ishikado, M. Horio, K. Koshiishi, S. Nakata, S. Ideta, K. Tanaka, K. Horiba, K. Ono, H. Kumigashira, T. Yoshida, S. Ishida, H. Eisaki, S. Shamoto, A. Fujimori
Summary: The study observed the possible superconductivity at the polar surfaces of 1111-type iron-based superconductors, which may be induced by the proximity effect from the bulk. Additionally, a large pseudogap was found to open on the surface-derived hole pockets, indicating a characteristic property of hole-doped iron-based superconductors.
PHYSICAL REVIEW RESEARCH
(2021)