Article
Chemistry, Physical
Zhongguo Li, Zhendong Wu, Xiaolong Wang, Hongtao Cao, Lingyan Liang, Junyi Yang, Yinglin Song
Summary: The study demonstrates the fabrication of amorphous zinc tin oxide thin films with strong visible light absorption using rf magnetron sputtering and rapid postannealing. The ultrafast carrier dynamics of the ternary films were investigated using femtosecond transient absorption spectroscopy, revealing that visible light absorption is induced by band gap reduction rather than defect states in the ZTO film. These findings shed light on the photophysical mechanism of amorphous ZTO films and suggest their potential use in solar cell and photodetector devices.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Yong Li, Xucai Kan, Xiansong Liu, Shuangjiu Feng, Qingrong Lv, Wei Wang, Chaocheng Liu
Summary: The cobalt-based inverse spinel oxides Co2Sn1-xTixO4 exhibit negative magnetization behavior and compensation temperature phenomenon, as well as spin-glass and large exchange bias behavior at low temperatures. The dilution effect of Ti and atomic disorder lead to the SG behavior and large exchange anisotropy in the system.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Laura M. Jacoby, Matthew J. Crane, Daniel R. Gamelin
Summary: This research discovers the potential application of vapor-deposited CsPbBr3 thin films in optoelectronic and spin-based devices. Both photogenerated holes and electrons show coherent spin precession, but the spin dephasing time of photogenerated electrons is shorter.
CHEMISTRY OF MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Amit Chanda, Deepika Rani, Derick Detellem, Noha Alzahrani, Dario A. Arena, Sarath Witanachchi, Ratnamala Chatterjee, Manh-Huong Phan, Hariharan Srikanth
Summary: This study investigates the temperature-dependent anomalous Nernst effect (ANE) and longitudinal spin Seebeck effect (LSSE) in CoFeCrGa thin films grown on MgO substrates. The results show that the MgO/CoFeCrGa films have high ANE and LSSE coefficients at room temperature, with peaks observed as the temperature increases.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Electrical & Electronic
Kota Hanzawa, Hidenori Hiramatsu
Summary: LaWN3 epitaxial thin films were successfully grown on α-Al2O3 (0001) substrates using a multi-cathode RF magnetron sputtering gun system with metal targets and nitrogen gas. The films exhibited n-type degenerate semiconducting behaviors, an enlarged optical band gap, and superconductivity at 0.73 K. However, they did not show the predicted ferroelectric properties due to off-stoichiometry. Alternative growth processes are needed to decrease carrier density and achieve ferroelectricity.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Materials Science, Ceramics
Hongfei Liu, Chenjun Zhang, Zhiping Zhang, Xiangdong Meng, Xianghua Zeng
Summary: Orthorhombic Sc2Mo3O12 films were successfully prepared via spin coating technique followed by annealing at 500-750 degrees C. The crystallinity of the films improved with higher post-annealing temperatures, demonstrating stable negative thermal expansion properties. The coefficients of thermal expansion in different directions were also determined, showing the overall shrinkage and expansion of the thin film.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Fangjuan Geng, Yu-Ning Wu, Daniel Splith, Liangjun Wang, Xiaowan Kang, Xiaojian Chen, Pengsheng Guo, Shanshan Liang, Lei Yang, Michael Lorenz, Marius Grundmann, Jiaqi Zhu, Chang Yang
Summary: By developing an amorphous Cu(S,I) material system, record high hole conductivities of 10(3)-10(4) S cm(-1) have been achieved in p-type amorphous transparent conductors (a-TCs), making them comparable with commercial n-type TCs made of indium tin oxide and 100 times greater than any previously reported p-type a-TCs. The high hole conduction is due to the overlap of large p-orbitals of I- and S2- anions, providing a hole transport pathway insensitive to structural disorder. Additionally, the bandgap of amorphous Cu(S,I) can be modulated from 2.6 to 2.9 eV by increasing the iodine content. These unique properties demonstrate the great potential of the Cu(S,I) system as a promising p-type amorphous transparent electrode material for optoelectronics.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Jiyang Huang, Daichi Oka, Yasushi Hirose, Masamichi Negishi, Tomoteru Fukumura
Summary: We grew thin films of Ti0.95Co0.05O2-δ, a room-temperature ferromagnetic semiconductor, on rigid and flexible glass substrates using TiO2 seed layers. The thin films exhibited a preferred (101) orientation and large crystallographic domains of around 50 μm in lateral size, showing clear ferromagnetic hysteresis loops at 300 K. The films also had high electrical conductivity and transparency, allowing for electrical and optical detection of the ferromagnetic signal through the anomalous Hall effect and magneto-optical effect, respectively. Interestingly, flatter films with larger domains were obtained on flexible glass substrates, leading to higher conductivity and larger anomalous Hall signals comparable to epitaxial thin films.
Article
Chemistry, Multidisciplinary
Irene Lucas, Noelia Marcano, Thomas Prokscha, Cesar Magen, Ruben Corcuera, Luis Morellon, Jose M. De Teresa, M. Ricardo Ibarra, Pedro A. Algarabel
Summary: This article provides a comprehensive magnetic characterization of the strain-induced segregated non-ferromagnetic layer (NFL), revealing spin glass behavior and confirming this through low-energy muon spectroscopy experiments.
Article
Materials Science, Multidisciplinary
Bipanko Kumar Mondal, Md. Ferdous Rahman, Jaker Hossain
Summary: We report the nonlinear optical properties of solution-processed indium selenide thin films. The films undergo a phase transformation from beta-In3Se2 to gamma-In2Se3 due to mechanical stress during annealing. Both phases show potential for nonlinear optical applications.
RESULTS IN PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Z. X. Chen, Y. Sakuraba, K. Masuda, X. D. Xu, L. S. R. Kumara, H. Tajiri, Y. Kotani, V Kushwaha, A. Perumal, K. Hono
Summary: In this study, the transport properties, microstructure, and atomic order of CoFeCrAl (CFCA) thin films were systematically analyzed. It was predicted that CFCA is a spin-gapless semiconductor (SGS), but experimental results revealed that one of the films lost this property after annealing. However, the film still exhibited some transport properties similar to those of a spin-gapless semiconductor.
Article
Chemistry, Physical
Muhammad Sheraz Khan, Bingsuo Zou, Li-Jie Shi, Shangfei Yao, Arfan Bukhtiar, WeiGuo Huang, Yang Lu, JiaJun Cao, Biling Zheng
Summary: Using Density Functional Theory (DFT), we investigated the opto-electronic and magnetic properties of Mn(II)-doped ZnTe thin films. The occupation of spin-up Mn-ta levels in the absence of additional carriers leads to a super-exchange mechanism. We studied the effect of additional p-type doping on the ferromagnetism and found that the coupling of hole carriers with spin-up Mn-states stabilizes ferromagnetism in the Mn(II)-doped ZnTe thin films. Additionally, Mn(II) doping widens ZnTe's bandgap and produces spin-forbidden d-d transition peaks, while p-type defects in the doped films improve the absorption efficiency.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Review
Chemistry, Multidisciplinary
Zhongkai Cheng, Deirdre M. O'Carroll
Summary: Photon recycling is crucial in the study of semiconductor materials, impacting their optoelectronic applications; however, further in-depth theoretical and experimental studies are needed to demonstrate its advantages and importance rigorously.
Article
Chemistry, Physical
Ho Jin, Clement Livache, Whi Dong Kim, Benjamin T. Diroll, Richard D. Schaller, Victor I. Klimov
Summary: The authors achieve a threefold enhancement in multiexciton yields in Mn-doped PbSe/CdSe quantum dots by exploiting spin-exchange interactions. These interactions outpace phonon emission losses and overcome the limitation of carrier multiplication. This study demonstrates the potential of spin-exchange carrier multiplication in advanced photoconversion.
Article
Chemistry, Physical
Pamella Vasconcelos Borges Pinho, Alain Chartier, Denis Menut, Antoine Barbier, Myrtille O. J. Y. Hunault, Philippe Ohresser, Cecile Marcelot, Benedicte Warot-Fonrose, Frederic Miserque, Jean-Baptiste Moussy
Summary: A quantitative link between chromium content, Fe2+/Fe3+ site-occupation and macroscopic physical properties of Fe3-xCrxO4 thin films is established using spectroscopic measurements and theoretical simulations. It is found that increasing chromium content delays the transition of Fe3-xCrxO4 thin films from inverse to normal spinel configuration and promotes collinear spin structure. The unique cation distribution in these thin films favors electron hopping and results in a smaller electronic band gap.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Tsukasa Katayama, Shishin Mo, Akira Chikamatsu, Yuji Kurauchi, Hiroshi Kumigashira, Tetsuya Hasegawa
Summary: In this study, GdBaCo2O6 epitaxial films were successfully synthesized and reversible transformation between x = 5.5 and 6 phases was achieved via low-temperature redox reactions. The x = 6 film exhibited ferromagnetic and metallic behavior below 110 K and semiconducting behavior above. The ferromagnetic interaction between Co3.5+ and Gd3+ contributed to the magnetization and the half-metallicity of the film.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Daisuke Asakura, Eiji Hosono, Miho Kitamura, Koji Horiba, Eisuke Magome, Hiroyuki Setoyama, Eiichi Kobayashi, Hayato Yuzawa, Takuji Ohigashi, Takaaki Sakai, Ryoichi Kanega, Takashi Funaki, Yukari Sato, Akihiro Ohira
Summary: In this study, X-ray absorption spectroscopy was used to investigate the electrolytes of a Ti-Mn redox flow battery, aiming to understand the redox reaction and precipitation formation. The results showed that the valence state of manganese in the precipitates is mostly 4+, while the solution only contains Mn2+.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Multidisciplinary Sciences
Kohei Fujiwara, Yasuyuki Kato, Hitoshi Abe, Shun Noguchi, Junichi Shiogai, Yasuhiro Niwa, Hiroshi Kumigashira, Yukitoshi Motome, Atsushi Tsukazaki
Summary: Amorphous semiconductors are widely used in electronic and energy-conversion devices. This study reveals that the short-range crystalline order in amorphous Fe-Sn films contributes to anomalous electrical and magneto-thermoelectric properties. This finding sheds light on the topology of amorphous materials and may enable the realization of functional topological amorphous electronic devices.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Zhiqiang Liao, Hiroyasu Yamahara, Kenyu Terao, Kaijie Ma, Munetoshi Seki, Hitoshi Tabata
Summary: In this research, the short-term memory capability of spin cluster glass based on the prevalent benchmark was quantitatively investigated. The results reveal that the magnetization relaxation of Co, Si-substituted Lu3Fe5O12 with spin glass behavior can provide higher short-term memory capacity than ferrimagnetic material without substitution. Therefore, materials with spin glass behavior can be considered as potential candidates for constructing next-generation spintronic reservoir computing with better performance.
SCIENTIFIC REPORTS
(2023)
Article
Multidisciplinary Sciences
Md Shamim Sarker, Lihao Yao, Hiroyasu Yamahara, Kaijie Ma, Zhiqiang Liao, Kenyu Terao, Siyi Tang, Sankar Ganesh Ramaraj, Munetoshi Seki, Hitoshi Tabata
Summary: This study explores a novel technique to systematically control magnon interference using asymmetric wavevectors from two different spin wave modes in a microstructured yttrium iron garnet crossbar. By modulating the thermal landscape and modifying the dispersion of the interfering spin wave modes, the study demonstrates phase reconfigurability in the interference pattern. This tunable interference can be used to implement reconfigurable logic gates operating between the XNOR and XOR modes.
SCIENTIFIC REPORTS
(2023)
Article
Nanoscience & Nanotechnology
M. Ohno, T. C. Fujita, Y. Masutake, H. Kumigashira, M. Kawasaki
Summary: Researchers have successfully synthesized two new metallic layered oxide compounds [BinOn+d]-[RhO2] (n = 2, 3) by pulsed laser deposition and subsequent annealing, and revealed dimensionality-dependent electrical transport behavior. This achievement paves the way for further exploration of novel layered oxide compounds.
Article
Materials Science, Multidisciplinary
Zhiqiang Liao, Keying Huang, Siyi Tang, Hiroyasu Yamahara, Munetoshi Seki, Hitoshi Tabata
Summary: This study proposes a one-dimensional lattice system based on hyperbolic nonlinearities as a logical stochastic resonance (LSR) system. Simulation experiments reveal that in the presence of noise, this system demonstrates strong stability and reliability, particularly with regards to pulse noise. These results highlight the superiority of the HOL-LSR system over traditional LSR systems.
RESULTS IN PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Kazuki Nagai, Masato Anada, Kazuhiro Kowa, Miho Kitamura, Hiroshi Kumigashira, Hiroo Tajiri, Yusuke Wakabayashi
Summary: It has been found that oxide films thinner than a few unit cells are often insulating, and the Anderson localization supported by low dimensionality is one of the major mechanisms for this behavior. To distinguish the effects of randomness from dimensionality, the structural fluctuation and average structure of LaNiO3 thin films on LaAlO3 substrates were examined as a function of thickness. Surface x-ray diffraction experiment revealed little difference in average atomic position and atomic occupancy between 2 to 5 u.c. thick samples, with the main difference observed in the atomic displacement parameters. This suggests that structural fluctuation plays a role in interfacial transport properties, which is often neglected in discussions of oxide interface physics.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Tatsuhiko Kanda, Daisuke Shiga, Asato Wada, Ryotaro Hayasaka, Yuuki Masutake, Naoto Hasegawa, Miho Kitamura, Kohei Yoshimatsu, Hiroshi Kumigashira
Summary: Quantized states in strongly correlated oxide nanostructures are crucial for designing quantum devices in future electronics. In situ ARPES measurements in SrTi1-xVxO3 reveal that the electron mean free path is a key parameter for controlling and designing quantized states in these structures.
COMMUNICATIONS MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Chuanlai Zang, Kaijie Ma, Yasuo Yano, Shuowei Li, Hiroyasu Yamahara, Munetoshi Seki, Tetsuya Iizuka, Hitoshi Tabata
Summary: The development of semiconductor gas sensors has the potential for noninvasive health monitoring through breath analysis. Tin oxide-copper oxide heterocomposite nanofibers were fabricated by electrospinning and calcination for ammonia sensing. The nanofibers showed enhanced ammonia-sensing response compared to pure tin oxide nanofibers, with a significant improvement in sensitivity at a SnO2:CuO ratio of 2:1. The mechanism and temperature-dependent response were also investigated, and a breath analysis application based on the fabricated sensors was demonstrated.
IEEE SENSORS JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Takuto Nakamura, Toru Nakaya, Yoshiyuki Ohtsubo, Hiroki Sugihara, Kiyohisa Tanaka, Ryu Yukawa, Miho Kitamura, Hiroshi Kumigashira, Keiichiro Imura, Hiroyuki S. Suzuki, Noriaki K. Sato, Shin-ichi Kimura
Summary: The electronic structure changes on the SmS surface under K doping are investigated using core-level photoelectron spectroscopy and angle-resolved photoelectron spectroscopy. The results show that the mean valence of Sm on the surface increases from nearly divalent to trivalent states with increasing K deposition. This carrier-induced valence transition (CIVT) from Sm2+ to Sm3+ is opposite to the conventional electron doping. The excess electrons from K atoms transfer to S sites, and the liberated electrons from Sm3+ ions due to CIVT are trapped around the Sm3+ ions like local excitons.
Article
Materials Science, Multidisciplinary
Asuka Honma, Daichi Takane, Seigo Souma, Yongjian Wang, Kosuke Nakayama, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Takashi Takahashi, Yoichi Ando, Takafumi Sato
Summary: By utilizing angle-resolved photoemission spectroscopy, we observed the band structure of three types of single-q antiferromagnetic domains at the surface of NdSb. We found that different surface domains exhibit different surface state formations and proposed that these surface states arise from symmetry breaking at the surface and the antiferromagnetic order.
Article
Materials Science, Multidisciplinary
D. Shiga, X. Cheng, T. T. Kim, T. Kanda, N. Hasegawa, M. Kitamura, K. Yoshimatsu, H. Kumigashira
Summary: Through in situ photoemission spectroscopy, the changes in the electronic structure of Cr-doped VO2 films on TiO2 substrates were investigated. The phase diagram of CrxV1-xO2 was obtained, showing the influence of strain effect on the metal-insulator transition temperature. The spectroscopic investigations revealed the changes in energy gap and V 3d states, as well as the existence of Mott insulating phase without V-V dimerization at high doping concentration.
Article
Materials Science, Multidisciplinary
Takuto Soma, Kohei Yoshimatsu, Koji Horiba, Hiroshi Kumigashira, Akira Ohtomo
Summary: The oxide superconductor Li1-xNbO2, with two-dimensional NbO2 layers, exhibits 2D superconductivity and large anisotropy in the upper critical field. The temperature-independent anisotropy suggests single-band superconductivity, which is different from other materials with similar structures. The study also reveals a narrow and correlated single band in the 2D NbO2 layers of Li1-xNbO2, similar to the superconductivity in cuprates.
