Article
Chemistry, Multidisciplinary
Yunpeng Yao, Haidong Jiang, Yu Peng, Xinyuan Zhang, Shuang Chen, Xitao Liu, Junhua Luo
Summary: The researchers have successfully developed a green bilayered hybrid double perovskite photoferroelectric with high Curie temperature and remarkable photoelectric properties, setting a new record in the field of multilayered hybrid perovskite ferroelectrics and providing insights for the rational design of high-performance photoelectric devices.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Materials Science, Multidisciplinary
Rahul Kumar, A. Sundaresan
Summary: In this paper, the field-induced ferroelectricity in BaHoFeO4 within a narrow range of applied magnetic fields (1.5 T H 5 T) is reported. Magnetization measurements reveal magnetic anomalies at TFe ordering of Fe3+, a possible spin structure change of Fe3+, and the antiferromagnetic ordering of Ho3+ sublattices. Heat capacity data did not show any anomaly at TNFe, but exhibited a broad N . Isothermal magnetization measurements indicate a metamagnetic transition at 1.5 T below 40 K. Temperature-dependent dielectric measurements below 1 T reveal two anomalies corresponding to Ho3+ ordering and a possible change in the magnetic phase of the Fe sublattice. These anomalies disappear at higher magnetic fields, and a different dielectric anomaly appears above the metamagnetic transition. A switchable electric polarization appears below 25 K and above the metamagnetic transition field (H 1.5 T), but disappears above 5 T.
Article
Chemistry, Physical
Yaguang Guo, Jian Zhou, Huanhuan Xie, Yanyan Chen, Qian Wang
Summary: In this study, stable 2D pentagonal transition metal compounds with polarization were identified through high-throughput screening and first-principles calculations. It was found that the polarization in these pentagonal monolayers arises from the orderly arranged polar bonds. These pentagonal monolayers exhibit significantly larger piezoelectric coefficients and photovaltaic shift current compared to elemental and binary pentagonal structures, expanding the family of pyroelectric materials and holding potential for energy conversions.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Chemistry, Inorganic & Nuclear
Jiaqi Ding, Hangren Li, Guoqiang Xi, Jie Tu, Jianjun Tian, Linxing Zhang
Summary: In this study, the researchers achieved increased tetragonality and reduced bandgaps in tetragonal-like phase BFO-based films through chemical strain. The tetragonality increased up to a large c/a of 1.239, and the bandgap decreased to 1.45 eV from 2.21 eV. This paper provides a new strategy for regulating the optical band gap of BFO and reveals its underlying mechanism.
INORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Multidisciplinary Sciences
H. Yamakawa, T. Miyamoto, T. Morimoto, N. Takamura, S. Liang, H. Yoshimochi, T. Terashige, N. Kida, M. Suda, H. M. Yamamoto, H. Mori, K. Miyagawa, K. Kanoda, H. Okamoto
Summary: Photoinduced phase transition is a central issue in the field of non-equilibrium quantum physics. The authors demonstrate that a terahertz electric-field pulse changes a Mott insulator of an organic molecular compound to a macroscopically polarized charge-order state.
NATURE COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Yaze Wu, Ibrahim Abdelwahab, Ki Chang Kwon, Ivan Verzhbitskiy, Lin Wang, Weng Heng Liew, Kui Yao, Goki Eda, Kian Ping Loh, Lei Shen, Su Ying Quek
Summary: The recent thrust toward flexible nanoscale devices has created a demand for two-dimensional piezoelectric materials. In this study, the authors found that NbOI2 flakes exhibit a large piezoelectric response, which is independent of thickness and has an electromechanical coupling factor near unity. Laser scanning vibrometer studies verified the huge piezoelectric responses of bulk and few-layer NbOI2 crystals, surpassing other internal references. Insights into the atomic origins of anti-correlated piezoelectric and ferroelectric responses in NbOX2 materials were also provided. This discovery calls for the development of NbOI2-based flexible nanoscale piezoelectric devices.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Qihang Liang, Fawei Zheng, Menglei Li
Summary: This study reports on a strain-modulated polar metal in the ferroelectric/metal superlattice of 1:1 KNbO3/CaNbO3. The structural distortions, including polar distortions and octahedral rotations, as well as layer-by-layer electronic structures in the superlattice under different epitaxial strains, were investigated. The results show that the polar displacements are influenced by the octahedral tilting pattern and interlayer electron transfer, and the in-plane polar distortions are enhanced by tensile strains. This research provides an efficient way to tune polar distortions and local metallicity via epitaxial strains in the superlattice.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Multidisciplinary Sciences
Shu Shi, Haolong Xi, Tengfei Cao, Weinan Lin, Zhongran Liu, Jiangzhen Niu, Da Lan, Chenghang Zhou, Jing Cao, Hanxin Su, Tieyang Zhao, Ping Yang, Yao Zhu, Xiaobing Yan, Evgeny Y. Tsymbal, He Tian, Jingsheng Chen
Summary: The authors demonstrate the stabilization of the metastable orthorhombic phase in Hf0.5 Zr0.5O2 films through interface engineering and hole doping.
NATURE COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Jian Zhou, Shunhong Zhang
Summary: The study proposes using a terahertz laser to trigger ferroic order switching in two-dimensional multiferroics, enhancing data storage density and read/write speed without damage. Through first-principles calculations, optically induced electronic, phononic, and mechanical responses of two experimentally fabricated multiferroic materials were investigated, showing the effective manipulation of stability in different orientation variants via laser polarization direction. The ultrafast transition kinetics and avoidance of conventional nucleation-growth phase transition processes were also demonstrated.
NPJ 2D MATERIALS AND APPLICATIONS
(2021)
Article
Physics, Applied
Boyuan Chi, Leina Jiang, Yu Zhu, Lingling Tao, Xiufeng Han
Summary: Through interface engineering, we propose an efficient way to achieve a sizable tunneling electroresistance (TER) effect in both SrRuO3/PbTiO3/FeO/Fe and SrRuO3/PbTiO3/CoO/Co MFTJ devices. The interfacial FeO or CoO layer can modify the band alignment between PbTiO3 barrier and electrodes, causing an insulating-metallic transition of the barrier and leading to a significant change in tunneling resistance. As a result, a giant TER effect of 10^5% is observed. Our findings suggest a practical method to enhance the TER effect in MFTJ devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Shaohui Qiu, Steven Rhodes, Huaxiang Fu
Summary: Using first-principles density functional theory, we discovered a giant hyperferroelectricity in LiZnSb, with a remarkably large spontaneous polarization of P = 0.282 C/m2 under an open-circuit boundary condition, one order of magnitude greater than LiNbO3. Additionally, LiZnSb exhibits exceptional stability in hyperferroelectricity, with a well depth of electric free energy AF = -332 meV, indicating its potential as a room-temperature hyperferroelectric solid. The origin of this giant hyperferroelectricity is attributed to the combination of a large mode effective charge of the soft longitudinal-optic phonon and a large high-frequency dielectric constant in LiZnSb.
Article
Materials Science, Multidisciplinary
Y. S. Tang, S. M. Wang, L. Lin, V. Ovidiu Garlea, Tao Zou, S. H. Zheng, H-M Zhang, J. T. Zhou, Z. L. Luo, Z. B. Yan, S. Dong, T. Charlton, J-M Liu
Summary: This study focuses on stabilizing the hexagonal structure of YbFeO3 through partial Sc substitution and revealing its canted antiferromagnetic state. The Fe3+ moments form a triangular configuration, while the Yb3+ moments order ferrimagnetically along the c axis. Additionally, the modulation of electric polarization induced by magnetic field at low temperature was achieved, indicating a coupling between ferroelectric and magnetic orders under magnetic field.
Article
Chemistry, Multidisciplinary
Ding-Chong Han, Yu-Hui Tan, Jia-Hui Wen, Yun-Zhi Tang, Peng-Fei Wu, Yu-Kong Li, Ming-Yang Wan, Xiao-Wei Fan
Summary: A neoteric high-temperature crown ether inclusion luminophor with excellent optical properties was constructed in this study, providing a new avenue for synthesizing phase-transition compounds with high-T-p and superior optical properties.
Article
Chemistry, Multidisciplinary
Mohammad Noor-A-Alam, Michael Nolan
Summary: Flexible two-dimensional piezoelectric materials, such as ferroelectric TiOX2 and multiferroelectric VOX2 monolayers, exhibit large in-plane piezoelectric coefficients. This makes them promising for applications in wearable electromechanical nano-devices.
Article
Nanoscience & Nanotechnology
Chao Yang, Miaogen Chen, Si Li, Xuanlin Zhang, Chenqiang Hua, Hua Bai, Chengcheng Xiao, Shengyuan A. Yang, Pimo He, Zhu-an Xu, Yunhao Lu
Summary: In this study, we predicted ferroelectricity in one-dimensional SbN and BiN nanowires and found that their polarization strengths are significantly higher than previously reported values. Additionally, we discovered that spontaneous spin polarization can be generated in these nanowires by moderate hole doping. This is the first reported instance of the coexistence of both ferroelectricity and ferromagnetism in a one-dimensional system.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Applied
Joel Molina-Reyes, Takuya Hoshii, Shun-Ichiro Ohmi, Hiroshi Funakubo, Atsushi Hori, Ichiro ujiwaral, Hitoshi Wakabayashi, Kazuo Tsutsui, Kuniyuki Kakushima
JAPANESE JOURNAL OF APPLIED PHYSICS
(2020)
Article
Physics, Applied
Haruki Tanigawa, Kentaro Matsuura, Iriya Muneta, Takuya Hoshii, Kuniyuki Kakushima, Kazuo Tsutsui, Hitoshi Wakabayashi
JAPANESE JOURNAL OF APPLIED PHYSICS
(2020)
Article
Physics, Applied
Junji Kataoka, Sung-Lin Tsai, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Kuniyuki Kakushima
Summary: The N-type conduction of sputter-deposited polycrystalline Al0.78Sc0.22N films was confirmed by Si ion implantation and activation annealing. However, the film surface is sensitive to humidity, leading to a significant increase in sheet resistance.
APPLIED PHYSICS EXPRESS
(2021)
Article
Physics, Applied
Jinhan Song, Atsuhiro Ohta, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Kuniyuki Kakushima
Summary: Enhanced oxidation of 4H-SiC surface was achieved in an oxygen-lean environment using a thin CeOx layer. By capping the CeOx layer with a SiO2 layer, high peak field mobility and a threshold voltage higher than 2 V were obtained, showing advantages over other gate oxide formation processes.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
Sung-Lin Tsai, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Tien-Kan Chung, Edward Y. Chang, Kuniyuki Kakushima
Summary: The crystallographic characteristics and ferroelectric properties of 50nm-thick sputter-deposited Al0.78Sc0.22N films deposited at room temperature and 400 degrees C were investigated. It was found that the films grew in the c-axis direction and exhibited poling-free ferroelectric properties. Despite low switching cycle endurance, metal-ferroelectric-metal capacitors showed high remnant polarization suitable for different deposition temperatures.
APPLIED PHYSICS LETTERS
(2021)
Editorial Material
Physics, Applied
Sung-Lin Tsai, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Tien-Kan Chung, Edward Y. Chang, Kuniyuki Kakushima
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Applied
Junji Kataoka, Sung-Lin Tsai, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Kuniyuki Kakushima
Summary: Research on 50 nm thick ferroelectric Al0.78Sc0.22N films with TiN electrodes revealed that the leakage current gradually shifted during initial switching, stabilizing at a specific value. This change was interpreted as the formation of a tunneling barrier due to nitrogen vacancies at the metal interface.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
Sung-Lin Tsai, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Tien-Kan Chung, Edward Yi Chang, Kuniyuki Kakushima
Summary: The study reveals the significant impact of thickness on the ferroelectric properties of Al0.78Sc0.22N films, with a gradual degradation of remnant polarization below 35 nm. Switching cycle tests show a wake-up effect in the films, especially for thick films.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
Takamasa Kawanago, Takahiro Matsuzaki, Ryosuke Kajikawa, Iriya Muneta, Takuya Hoshii, Kuniyuki Kakushima, Kazuo Tsutsui, Hitoshi Wakabayashi
Summary: This paper presents the device concept for achieving high-gain operation of a tungsten diselenide (WSe2) complementary metal-oxide-semiconductor (CMOS) inverter at a low power supply voltage. The concept involves developing a doping technique and gate stack technology. By spin-coating with a fluoropolymer and poly(vinyl alcohol) (PVA), both electrons and holes can be doped to WSe2. Furthermore, a hybrid self-assembled monolayer/aluminum oxide (AlO(x)) gate dielectric is used to enhance gate capacitance and interfacial properties. The experimental results demonstrate a high gain of 9 at a supply voltage of 0.5V. This study paves the way for the future research and development of devices and circuits based on transition metal dichalcogenides.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Sung-Lin Tsai, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Tien-Kan Chung, Edward Yi Chang, Kuniyuki Kakushima
Summary: The effects of field cycling on ferroelectric properties of Al0.78Sc0.22N capacitors were investigated. The research found that in the early switching cycles, the switching voltage decreased, possibly due to the formation of nitrogen-vacancy facilitating atom displacements. Fatigue effect was observed in further switching cycles, especially in domains with low switching voltage. Leakage current analysis showed a continuous reduction in the Schottky barrier height for electrons with increasing number of switching cycles. The breakdown of Al0.78Sc0.22N films was triggered by excessive leakage current causing Joule heat.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Kazuto Mizutani, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Edward Y. Chang, Kuniyuki Kakushima
Summary: The effects of a 1 nm thick CeO(x) capping layer on the ferroelectric characteristics of Y-doped HfO2 films were investigated. The results showed that the capping layer shortened the time required to stabilize the ferroelectric phase, increased the remnant polarization, and suppressed the formation of conductive filaments. Therefore, the CeO(x) capping layer is effective in promoting the ferroelectric phase in HfO2 with high switching endurance.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Si-Meng Chen, Sung-Lin Tsai, Kazuto Mizutani, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui, Edward Yi Chang, Kuniyuki Kakushima
Summary: A method for shifting the threshold voltage (Vth) in GaN high electron mobility transistors using self-upward polarized Al1-xScxN gate dielectrics is proposed. The direction of spontaneous polarization is controlled by inserting an Al2O3 layer. A Vth shift of 8 V is achieved by changing the polarization direction. The thickness scaling in the Al1-xScxN layer shows a linear relationship to Vth, indicating a high spontaneous polarization. With the combination of a recess process, it is feasible to achieve a high positive Vth for enhancement-mode operation.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
M. Nishizawa, T. Hoshii, H. Wakabayashi, K. Tsutsui, Y. Daigo, I Mizushima, T. Yoda, K. Kakushima
Summary: This paper proposes a method for using device simulation to extract the hole lifetime of a thin n-type SiC epitaxial layer. By correlating the voltage drop across a forward-biased pn diode and parallel pn diodes at the same current density with the defined hole lifetime, the hole lifetime can be extracted. It was found that there was a severe error in the extraction of the voltage drop, which was attributed to surface recombination. The introduction of a field-plate between the anodes recovered the extraction error, achieving an extraction accuracy of 99% even with a high surface recombination velocity.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Atsuki Miyata, T. Hoshii, H. Wakabayashi, K. Tsutsui, K. Kakushima
Summary: This paper investigates a photodetector based on an AlGaN/GaN high electron mobility transistor on Si, which exhibits long decay time after removal of light irradiation, making it unsuitable for applications requiring fast response. The decay time is successfully suppressed from 75 to 2 seconds by modulating the substrate voltage.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
