Article
Optics
Xinru Wang, Ying Ding, M. N. Chen, Z. B. Siu, Mansoor B. A. Jalil, Yuan Li
Summary: We studied the effect of strain on the Td-MoTe2 heterojunction and found that the strain-induced photocurrent exhibits anisotropy depending on the strain direction. The transport properties and magnitude of the photocurrent in the MoTe2-based device can be effectively modulated by adjusting the strength and direction of the strain.
Article
Physics, Applied
Boyuan Di, Xiaokun Wen, Wenyu Lei, Yuhui Zhang, Liufan Li, Xinyue Xu, Wenchao Kong, Haixin Chang, Wenfeng Zhang
Summary: We have demonstrated that the carrier polarity of MoTe2 transistors can be modulated by controlling the channel thickness using NiTe2 semimetal contacts. The transition from symmetric ambipolar conduction to unipolar p-type polarity occurs as the channel thickness decreases, and this is attributed to the synergistic effect of channel thickness-dependent band alignment and charge transfer behavior with unique NiTe2 semimetal contacts.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Yong Zhang, Fucong Fei, Ruxin Liu, Tongshuai Zhu, Bo Chen, Tianyu Qiu, Zewen Zuo, Jingwen Guo, Wenchao Tang, Lifan Zhou, Xiaoxiang Xi, Xiaoshan Wu, Di Wu, Zhicheng Zhong, Fengqi Song, Rong Zhang, Xuefeng Wang
Summary: By studying Ta-doped Mo1-xTaxTe2 single crystals, it is found that Ta doping can significantly enhance the superconductivity, with a transition temperature of up to 7.5 K. An enhanced perpendicular upper critical field of 14.5 T exceeding the Pauli limit is also observed, indicating the possible emergence of unconventional mixed singlet-triplet superconductivity and inversion symmetry breaking.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Tianyang Wang, Xuan Luo, Jingjing Gao, Zhongzhu Jiang, Wei Wang, Xingcai Yang, Nan Zhou, Xiaoguang Zhu, Lei Zhang, Wenjian Lu, Wenhai Song, Hongyan Lv, Yuping Sun
Summary: Fe-intercalated T-d-FexMoTe2 single crystals (0 < x < 0.15) were successfully grown and it was found that the phase transition temperature T-S is gradually suppressed with increasing x. Theoretical calculation suggests that the increased energy of the T-d phase, enhanced transition barrier, and more occupied bands in 1T' phase is responsible for the suppression in T-S. In addition, a rho(alpha)-lnT behavior induced by Kondo effect is observed with x >= 0.08, due to the coupling between conduction carriers and the local magnetic moments of intercalated Fe atoms. A spin-glass transition occurs at approximate to 10 K for T-d-Fe0.15MoTe2. The calculated band structure of T-d-Fe0.25MoTe2 shows that two flat bands exist near the Fermi level, which are mainly contributed by the d(yz) and dx2-y2 orbitals of the Fe atoms. The electronic phase diagram of T-d-FexMoTe2 is established for the first time in this work.
ADVANCED MATERIALS
(2023)
Article
Multidisciplinary Sciences
Zheyi Zhu, Stephan Kim, Shiming Lei, Leslie M. Schoop, R. J. Cava, N. P. Ong
Summary: This study investigates the MAR features in high-transparency SNS junctions based on the Dirac semimetal MoTe2. It is found that MARs coexist with a Josephson supercurrent, and the amplitude of the supercurrent varies with the MAR order as the junction voltage is varied. The experiment measures the coherence of Cooper pairs shuttling across the junction and reveals a direct relation between the coherence and MARs. Surprisingly, the superconductivity in MoTe2 does not affect the MAR features.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Chemistry, Multidisciplinary
Pingbo Chen, Gongqi Wang, Bicong Ye, Jinhua Wang, Liang Zhou, Zhenzhong Tang, Le Wang, Jiannong Wang, Wenqing Zhang, Jiawei Mei, Weiqiang Chen, Hongtao He
Summary: This study reveals that planar Josephson junctions based on type-II Weyl semimetal MoTe2 exhibit a prominent superconducting diode effect, with the asymmetry of this effect effectively modulated by an external magnetic field. Moreover, it is demonstrated that these junctions have a rectification efficiency of up to 50.4%.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Alexandra N. N. Perevalova, Sergey V. V. Naumov, Vyacheslav V. V. Marchenkov
Summary: In this study, Weyl semimetal MoTe2 single crystal was grown using the chemical vapor transport method, and its electrical resistivity, magnetoresistivity, and Hall effect were investigated. The results showed that both the electrical resistivity and the conductivity of MoTe2 follow a quadratic temperature law in the absence of a magnetic field, suggesting a possible electron-phonon-surface interference scattering mechanism. The Hall effect in MoTe2 was analyzed using single-band and two-band models, with the latter being more suitable for systems containing different groups of current carriers.
Article
Nanoscience & Nanotechnology
Jiatong Mao, Youqi Zhang, Yinuo Zhang, Yunan Lin, Yao Feng, Yongqi Hu, Muhammad Shafa, Yi Pan
Summary: Here, we report the synthesis and application of 1 inch wafer-scale polycrystalline few layer 1T'-MoTe2 on the SiO2/Si substrate by employing a modified chemical vapor deposition method of predeposition of precursors. The device shows sensitivity to a wide spectra range while maintaining high performance of the ON/OFF ratio, responsivity, and specific detectivity. Our work may promote the potential application of a self-powered high-performance photodetector based on 1T'-MoTe2.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
King Yau Yip, Siu Tung Lam, Kai Ham Yu, Wing Shing Chow, Jiayu Zeng, Kwing To Lai, Swee K. Goh
Summary: Researchers applied biaxial strain on a thin single crystalline MoTe2 using the differential thermal expansion between dissimilar materials, successfully increasing its superconducting critical temperature by fivefold and expanding the superconducting region significantly. This simple and versatile approach can be used to tune the electronic properties of MoTe2 and other quantum materials.
Article
Physics, Multidisciplinary
Ryoya Matsumoto, Naurang L. Saini, Alessio Giampietri, Viktor Kandyba, Alexey Barinov, Rajveer Jha, Ryuji Higashinaka, Tatsuma D. Matsuda, Yuji Aoki, Takashi Mizokawa
Summary: Investigation on the electronic structure of MoTe2 undergoing a monoclinic-orthorhombic transition around 250K using various techniques reveals modifications in electron and hole pockets similar to WTe2 due to electronic correlation. Different surface states are observed in different domains of MoTe2 cleaved in the low temperature orthorhombic phase, suggesting a potential correlation between surface states and monoclinic-orthorhombic transition.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2021)
Article
Materials Science, Multidisciplinary
Haoxiong Zhang, Awabaikeli Rousuli, Kenan Zhang, Haoyuan Zhong, Yang Wu, Pu Yu, Shuyun Zhou
Summary: Manipulating the strength of interlayer coupling is an effective strategy to induce intriguing properties in layered materials. Recent studies have reported enhanced superconductivity in Weyl semimetal MoTe2 and WTe2 through ionic liquid (IL) cation intercalation. In this study, by inserting IL cations with different sizes into MoTe2, the interlayer spacing of the intercalated MoTe2 samples was tuned, revealing the dependence of superconducting transition temperature T(c) on the interlayer spacing. The results show that T(c) increases with the interlayer spacing, indicating the importance of weakened interlayer coupling in superconductivity. Interestingly, the intercalation-induced superconductivity exhibits a high Ginzburg-Landau anisotropy, suggesting a quasi-two-dimensional nature where adjacent superconducting layers are coupled through Josephson tunneling.
Article
Materials Science, Multidisciplinary
Maanwinder P. Singh, Jonas Kiemle, Ilkay Ozdemir, Philipp Zimmermann, Takashi Taniguchi, Kenji Watanabe, Marko Burghard, Olcay Uezengi Aktuerk, Christoph Kastl, Alexander W. Holleitner
Summary: This study investigates the impact of crystal phase disorder on the generation of helicity-dependent photocurrents in layered MoTe2. By using scanning photocurrent microscopy, the phase transition and hysteresis between different crystal phases are spatially probed. The results reveal a highly disordered photocurrent response in the intermediate temperature regime, and suggest that the helicity-dependent and ultrafast photocurrents are likely due to a local breaking of the electronic symmetries. These findings highlight the significance of local domain morphologies and ultrafast relaxation dynamics on the optoelectronic properties of low-dimensional van der Waals circuits.
Article
Nanoscience & Nanotechnology
Lingxian Kong, Guangliang Li, Qi Su, Xianhua Tan, Xuning Zhang, Zhiyong Liu, Guanglan Liao, Bo Sun, Tielin Shi
Summary: This study demonstrates the use of a MoTe2/MoS2 2D heterojunction to improve the performance of photodetectors and achieve polarization-sensitive, self-powered, and broadband photodetection and imaging. The device has a self-powered photoresponse ranging from 520 to 1550 nm due to the built-in electric field of the heterojunction. Under 915 nm light illumination, the device shows outstanding performance, including high responsivity, specific detectivity, fast rise/decay time, and high on/off ratio. The polarization imaging capabilities of the device in scattering surroundings are also demonstrated, with significant contrast enhancement compared to S-0. This work opens up new avenues for developing high-performance polarization-sensitive photodetection and next-generation polarized imaging using anisotropic semimetals heterojunction photodetectors.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Souvik Biswas, Aurelie Champagne, Jonah B. Haber, Supavit Pokawanvit, Joeson Wong, Hamidreza Akbari, Sergiy Krylyuk, Kenji Watanabe, Takashi Taniguchi, Albert Davydov, Zakaria Y. Al Balushi, Diana Y. Qiu, Felipe H. da Jornada, Jeffrey B. Neaton, Harry A. Atwater
Summary: This study experimentally investigates the excitonic luminescence properties of monolayer MoTe2 and reveals the temperature dependence and interplay between exciton and trion. The results demonstrate that these properties are influenced by free-carrier screening, Pauli blocking, and band gap renormalization, in agreement with theoretical calculations. These findings contribute to the potential applications of monolayer MoTe2 in near-infrared optoelectronics and photonic devices.
Article
Chemistry, Physical
Rovi Angelo B. Villaos, Harvey N. Cruzado, John Symon C. Dizon, Aniceto B. Maghirang, Zhi-Quan Huang, Chia-Hsiu Hsu, Shin-Ming Huang, Hsin Lin, Feng-Chuan Chuang
Summary: This study investigates the effects of thin-film thickness on transition metal dichalcogenides, revealing the tunability of electronic properties of ZrX2 thin films due to thickness dependence and strain. The research demonstrates that ZrX2 adopts the 1T phase as the most stable structure, with varying band gaps and the potential for superconductivity in certain thin films.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Ya Deng, Chao Zhu, Yu Wang, Xiaowei Wang, Xiaoxu Zhao, Yao Wu, Bijun Tang, Ruihuan Duan, Kun Zhou, Zheng Liu
Summary: Two-dimensional (2D) materials, including 2D arrays with emerging properties, have great potentials in high-density electric devices and advanced integrated circuits. However, the controllable synthesis of large arrays of 2D elements remains unsolved. In this study, a one-step chemical vapor deposition (CVD) synthesis strategy was developed to achieve single-crystalline MoTe2 nanoribbon arrays directly on a normal SiO2/Si substrate without the need for special substrates or post-processing. The synthesized ribbons were well-aligned and had a density ten times higher than reported in previous studies on MoS2. The crystal-structure boosted solid-liquid-vapor (SLV) self-etching mechanism was revealed through scanning transmission electron microscopy (STEM) and first-principles calculations. These findings provide a convenient synthesis strategy for high-density nanoarrays that can be used as platforms for integrated nanoscale electric devices.
Article
Chemistry, Physical
Xueting Dai, Feng Qin, Caiyu Qiu, Ling Zhou, Junwei Huang, Fanghua Cheng, Xiangyu Bi, Caorong Zhang, Zeya Li, Ming Tang, Shengqiang Wu, Xiaoxu Zhao, Yangfan Lu, Huiyang Gou, Hongtao Yuan
Summary: The interaction between light and matter in low-dimensional quantum-confined structures can greatly influence the optical properties of materials and have applications in optoelectronics. In the anisotropic layered silicon diphosphide (SiP2) crystal, the quasi-one-dimensional (1D) phosphorus-phosphorus (P-P) chains create an unconventional quasi-1D excitonic state and a unique 1D quantum-confined system. By alloying SiP2 with a similar element, researchers can study the properties of these excitons and phonons associated with the quasi-1D P-P chains, as well as their strong interaction. However, the experimental observation and understanding of SiP2 with isoelectronic dopants is still unclear. In this study, the authors use photoluminescence and Raman spectroscopy measurements to observe the redshift of the confined excitonic peak and the stiffening of the phonon vibration mode in Si(P1-xAsx)2 alloys with increasing arsenic (As) compositions. This anomalous stiffening is attributed to the selective substitution of As atoms for P atoms within the P-P chains, as confirmed by scanning transmission electron microscopy. These optical spectrum changes provide insights into 1D quantum confinement in semiconductors and offer opportunities for photonic device applications.
Article
Chemistry, Multidisciplinary
Yahuan Huan, Tiantian Luo, Xiaocang Han, Jun Ge, Fangfang Cui, Lijie Zhu, Jingyi Hu, Feipeng Zheng, Xiaoxu Zhao, Lili Wang, Jian Wang, Yanfeng Zhang
Summary: This study reports the composition-controllable synthesis of 2D non-layered iron selenide nanosheets and explores their fundamental properties as self-intercalation induced novel TMDs compounds, providing a new direction for their application explorations in nanoelectronics and spintronics-related fields.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Qin Liu, Shibo Xi, Xinnan Peng, Lei Feng, Guangyuan Xu, Zhendong Liu, Yuan Kong, Xiaoxu Zhao, Huan Yan
Summary: This study proposes a new strategy for investigating the coordination environment of catalytic centers and its effect on reactivity. By altering the surrounding atoms instead of the catalytic metal center, a clear relationship between coordination environment and catalytic activity was observed. DFT calculations provided a comprehensive map of the relationship between coordination environments and catalytic performances. This coordination environment engineering method can be widely applied to screen new catalysts and offers a novel way to investigate the fundamental chemistry of active sites in catalysis.
Article
Chemistry, Multidisciplinary
Xiaocang Han, Jing-Yang You, Shengqiang Wu, Runlai Li, Yuan Ping Feng, Kian Ping Loh, Xiaoxu Zhao
Summary: Transition-metal trihalides MX3 belong to a family of novel 2D magnets with topological magnons and electromagnetic properties, showing great potential in next-generation spintronic devices. However, direct atomic-scale analysis of MX3 is challenging due to their air instability, making information on stacking-registry-dependent magnetism elusive. In this study, we report a nondestructive transfer method to realize intact transfer of bilayer MX3 and provide a full spectrum of stacking orders in MX3 with atomic precision, revealing their associated magnetic ground states. The study sheds light on the structural basis of diverse magnetic orders in MX3, paving the way for modulating magnetic couplings via stacking engineering.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Qiangbing Guo, Xiao-Zhuo Qi, Lishu Zhang, Meng Gao, Sanlue Hu, Wenju Zhou, Wenjie Zang, Xiaoxu Zhao, Junyong Wang, Bingmin Yan, Mingquan Xu, Yun-Kun Wu, Goki Eda, Zewen Xiao, Shengyuan A. Yang, Huiyang Gou, Yuan Ping Feng, Guang-Can Guo, Wu Zhou, Xi-Feng Ren, Cheng-Wei Qiu, Stephen J. Pennycook, Andrew T. S. Wee
Summary: A van der Waals crystal, niobium oxide dichloride (NbOCl2), has been found to exhibit weakened interlayer electronic coupling and monolayer-like excitonic behavior in the bulk form. It also has a scalable second-harmonic generation intensity that is three orders higher than that in monolayer WS2. Additionally, the strong second-order nonlinearity in thin flakes as thin as 46 nm enables correlated parametric photon pair generation through a spontaneous parametric down-conversion (SPDC) process. This is the first SPDC source demonstrated in two-dimensional layered materials and the thinnest SPDC source ever reported. This research opens avenues for developing van der Waals material-based ultracompact on-chip SPDC sources and high-performance photon modulators in both classical and quantum optical technologies.
Article
Materials Science, Multidisciplinary
Ibrahim Abdelwahab, Benjamin Tilmann, Xiaoxu Zhao, Ivan Verzhbitskiy, Rodrigo Berte, Goki Eda, William L. Wilson, Gustavo Grinblat, Leonardo de S. Menezes, Kian Ping Loh, Stefan A. Maier
Summary: Parametric infrared upconversion is a nonlinear optical process that converts low-frequency IR photons into high-frequency ultraviolet/visible photons. It is of great importance for various applications, such as security, material science, and healthcare. However, the upconversion efficiency for nanometer-scale materials is typically very low due to limited depth of excitation fields.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Renji Bian, Guiming Cao, Er Pan, Qing Liu, Zefen Li, Lei Liang, Qingyun Wu, Lay Kee Ang, Wenwu Li, Xiaoxu Zhao, Fucai Liu
Summary: Sliding ferroelectricity associated with interlayer translation is a promising approach for miniaturizing ferroelectric devices. However, the weak polarization limits the performance of sliding ferroelectric transistors, leading to a low on/off ratio and a narrow memory window. To overcome this, we propose a simple strategy to regulate the Schottky barrier in sliding ferroelectric semiconductor transistors based on gamma-InSe, resulting in high performance with a large on/off ratio (106) and a wide memory window (4.5V). Furthermore, the memory window can be modulated by electrostatic doping or light excitation. These findings provide new opportunities for designing novel ferroelectric devices based on emerging sliding ferroelectricity.
Article
Multidisciplinary Sciences
Huifeng Tian, Yinhang Ma, Zhenjiang Li, Mouyang Cheng, Shoucong Ning, Erxun Han, Mingquan Xu, Peng-Fei Zhang, Kexiang Zhao, Ruijie Li, Yuting Zou, PeiChi Liao, Shulei Yu, Xiaomei Li, Jianlin Wang, Shizhuo Liu, Yifei Li, Xinyu Huang, Zhixin Yao, Dongdong Ding, Junjie Guo, Yuan Huang, Jianming Lu, Yuyan Han, Zhaosheng Wang, Zhi Gang Cheng, Junjiang Liu, Zhi Xu, Kaihui Liu, Peng Gao, Ying Jiang, Li Lin, Xiaoxu Zhao, Lifen Wang, Xuedong Bai, Wangyang Fu, Jie-Yu Wang, Maozhi Li, Ting Lei, Yanfeng Zhang, Yanglong Hou, Jian Pei, Stephen J. Pennycook, Enge Wang, Ji Chen, Wu Zhou, Lei Liu
Summary: By varying the growth temperatures, the degree of disorder and electrical conductivity of amorphous carbon films can be tuned, revealing the causal link between microstructures and macroscopic properties of amorphous materials.
Article
Chemistry, Multidisciplinary
Zhuoping Wang, Kai Chi, Shengxiong Yang, Junwu Xiao, Fei Xiao, Xiaoxu Zhao, Shuai Wang
Summary: Developing efficient electrocatalysts for hydrogen evolution reaction (HER) under various pH conditions and large-scale hydrogen production is critical and challenging. This study presents a tailoring strategy to fabricate an excellent HER catalyst, NC@Ru-SA-CoP, which consists of high-density atomically dispersed Ru sites anchored in CoP nanoparticles supported on carbon spheres. The catalyst exhibits outstanding performance in both acidic and alkaline electrolytes, with low overpotentials in KOH and H2SO4. The constructed alkaline anion exchange membrane water electrolyzer demonstrates remarkable durability and industrial-scale current density. This strategy provides a new perspective for designing Ru-based electrocatalysts and advancing industrial-scale hydrogen production.
Article
Materials Science, Multidisciplinary
Mengwei Han, Shengqiang Wu, Xiaoxu Zhao, Qinming He, Bangmin Zhang, Weiming Xiong, Xin Luo, Yue Zheng
Summary: This study explores the Raman modes and phonon properties of trapezoidal Bi2O2Se grown through substrate engineering. Additional Raman modes at 55 and 429 cm(-1) were detected on the slope of the trapezoid, while 159 and 362 cm(-1) modes were found on the top plane. The crystal orientation was determined using polarized Raman spectroscopy, density functional theory calculations, and group theory analysis. The thermal anisotropy of trapezoidal Bi2O2Se was also investigated. These findings have implications for potential nanoelectronic applications of Bi2O2Se.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Yi Zeng, Shengqiang Wu, Xiaolong Xu, Biao Zhang, Bo Han, Zijing Zhao, Yu Pan, Feng Wang, Qi Wang, Yuqia Ran, Peng Gao, Xiaoxu Zhao, Yu Ye, Yanglong Hou
Summary: This study develops a stable method for synthesizing the metallic Mo x W1-x Te2 and obtains large-area Mo x W1-x Te2/2H-MoTe2 in-plane metal-semiconductor structures in one step. The fabricated field-effect transistors exhibit good electrical characteristics due to the unique 2D in-plane epitaxial mechanism. The large-area 2D metal-semiconductor heterostructure arrays can be transferred onto flexible substrates, showing promising applications in flexible electronics.
ACS MATERIALS LETTERS
(2023)
Article
Multidisciplinary Sciences
Zijing Zhao, Zhi Fang, Xiaocang Han, Shiqi Yang, Cong Zhou, Yi Zeng, Biao Zhang, Wei Li, Zhan Wang, Ying Zhang, Jian Zhou, Jiadong Zhou, Yu Ye, Xinmei Hou, Xiaoxu Zhao, Song Gao, Yanglong Hou
Summary: A general thermodynamics-triggered competitive growth (TTCG) model and a universal hydrate-assisted chemical vapor deposition strategy were proposed to synthesize various 2D nonlayered transition metal oxides with room-temperature magnetic properties. This study provides new theoretical and experimental approaches for the synthesis of 2D nonlayered materials.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Zhang Zhou, Xiaoxu Zhao, Liangmei Wu, Hongtao Liu, Jiancui Chen, Chuanyin Xi, Zhaosheng Wang, Enke Liu, Wu Zhou, Stephen J. Pennycook, Sokrates T. Pantelides, Xiao-Guang Zhang, Lihong Bao, Hong-Jun Gao
Summary: This study reports a dimensional crossover in self-intercalated antiferromagnetic V5S8 nanoflakes. The transition from three-dimensional to two-dimensional transport is observed when the thickness of V5S8 flakes is reduced to a certain value. The emergence of Kondo physics and the change in magnetoresistance indicate the influence of dimensional crossover on the electronic properties of 2D metallic transition-metal dichalcogenides (TMDs).
Review
Engineering, Electrical & Electronic
Bijun Tang, Dianyi Hu, Xiaoxu Zhao, Xiaowei Wang, Zheng Liu
Summary: In recent years, there has been significant research interest in two-dimensional magnetic transition metal chalcogenides (TMCs) due to their important properties in developing future electronic and spintronic devices. This review provides an introduction to recent developments in the preparation of 2D magnetic TMCs, particularly chromium and iron-based chalcogenides, as well as their structures and intriguing magnetic phenomena. The common crystal structures of magnetic TMCs are discussed, along with various chemical vapor deposition strategies for synthesizing them. Additionally, the physical properties associated with 2D TMCs, such as magnetic anisotropy, thickness, phase-dependent magnetic response, and stability, are summarized. Challenges and future research directions in this field are also briefly discussed based on recent advances.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
