Article
Nanoscience & Nanotechnology
Andres Granados del aguila, Yi Ren Wong, Indrajit Wadgaonkar, Antonio Fieramosca, Xue Liu, Kristina Vaklinova, Stefano Dal Forno, T. Thu Ha Do, Ho Yi Wei, Kristina Watanabe, T. Taniguchi, Kostya S. Novoselov, Maciej Koperski, Marco Battiato, Qihua Xiong
Summary: This study presents experimental evidence of a collective state of short-lived excitons in a direct-bandgap, atomically thin MoS2 semiconductor. The propagation of the exciton fluid resembles that of a classical liquid, as indicated by the nearly uniform photoluminescence through the MoS2 monolayer. The exciton fluid flows over ultralong distances at a speed of approximately 6% the speed of light.
NATURE NANOTECHNOLOGY
(2023)
Review
Chemistry, Multidisciplinary
Michael S. Lodge, Shengyuan A. Yang, Shantanu Mukherjee, Bent Weber
Summary: Atomically thin topological materials, such as the quantum spin Hall insulator, show great potential for applications in quantum computing and electronic devices, with large tunable bulk bandgaps and gapless edge states.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Tristan L. Britt, Qiuyang Li, Laurent P. Rene de Cotret, Nicholas Olsen, Martin Otto, Syed Ali Hassan, Marios Zacharias, Fabio Caruso, Xiaoyang Zhu, Bradley J. Siwick
Summary: Through ultrafast electron diffraction and diffuse scattering, the study directly quantifies electron-phonon coupling in monolayer molybdenum disulfide and phonon transport to a silicon nitride substrate. Optically generated hot carriers lead to an anisotropic distribution of phonons in the monolayer, with dielectric screening playing an essential role in weakening the electron-phonon coupling.
Article
Multidisciplinary Sciences
Jekwan Lee, Wonhyeok Heo, Myungjun Cha, Kenji Watanabe, Takashi Taniguchi, Jehyun Kim, Soonyoung Cha, Dohun Kim, Moon-Ho Jo, Hyunyong Choi
Summary: By utilizing a heterobilayer of MoS2/WTe2, this study demonstrates a unipolar VHE with enhanced lifetime and mobility, tackling the issue of fast valley depolarization in traditional exciton-based VHE. Spin polarized electrons injected from WTe2 into MoS2 lead to prolonged valley-polarized lifetime and increased valley Hall mobility.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Applied
Junji Haruyama
Summary: The passage primarily introduces the research and applications of 2D topological insulators and quantum spin Hall phases, focusing on their potential applications in dissipationless spintronic devices, as well as the development of innovative quantum devices in atomically thin layers such as graphene.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Yan Zeng, Wei Dai, Rundong Ma, Zhe Li, Zhenwei Ou, Cheng Wang, Yiling Yu, Tong Zhu, Xiaoze Liu, Ti Wang, Hongxing Xu
Summary: This study reports the energy transfer process in MoS2/WS2 heterostructures, obtaining an ET rate of approximately 240 fs by analyzing various interfaces. This elucidates the role of the ET process in interfacial carrier dynamics and provides guidance for engineering interfaces.
Article
Chemistry, Physical
Yi-Chao Zou, Lucas Mogg, Nick Clark, Cihan Bacaksiz, Slavisa Milanovic, Vishnu Sreepal, Guang-Ping Hao, Yi-Chi Wang, David G. Hopkinson, Roman Gorbachev, Samuel Shaw, Kostya S. Novoselov, Rahul Raveendran-Nair, Francois M. Peeters, Marcelo Lozada-Hidalgo, Sarah J. Haigh
Summary: This study investigates the dynamics of ion exchange in atomically thin materials, revealing that ion diffusion in few-layer two-dimensional clays approaches that of free water, and superlattice cation islands can form in twisted and restacked materials.
Article
Nanoscience & Nanotechnology
Bin Shi, Xuehui Gan, Kang Yu, Haojie Lang, Xing'an Cao, Kun Zou, Yitian Peng
Summary: This study investigates and regulates the friction and dissipation on atomically thin MoS2 by tuning the carrier concentration. The electronic contribution to energy dissipation during the friction process was confirmed and regulated through gate-modulation. The research provides a utility approach to tune the friction intelligently on semiconductive two-dimensional materials and achieve superlubric properties.
NPJ 2D MATERIALS AND APPLICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Tahmid Kaisar, Jaesung Lee, Donghao Li, Steven W. Shaw, Philip X. -L. Feng
Summary: This study reports on the nonlinear dynamic characteristics of ultimately thin nanomechanical resonators built upon single-layer, bilayer, and trilayer molybdenum disulfide vibrating membranes. Through experimental measurements and quantitative analyses, the nonlinear damping and stiffness coefficients at cubic and quintic orders were determined for these two-dimensional resonators. The study highlights the importance of considering the quintic force in nonlinear dynamics analysis.
Article
Chemistry, Multidisciplinary
Roberto Rosati, Koloman Wagner, Samuel Brem, Raul Perea-Causin, Jonas D. Ziegler, Jonas Zipfel, Takashi Taniguchi, Kenji Watanabe, Alexey Chernikov, Ermin Malic
Summary: Through a joint theory-experiment study, it has been discovered that dark excitons play a crucial role in the spatial propagation of excitons in atomically thin materials. The initial population of dark exciton states by emission from bright states leads to rapid expansion of hot excitons and a transient increase in the diffusion coefficient. These findings are significant for both fundamental understanding and technological applications.
Article
Multidisciplinary Sciences
Jianbo Yin, Cheng Tan, David Barcons-Ruiz, Iacopo Torre, Kenji Watanabe, Takashi Taniguchi, Justin C. W. Song, James Hone, Frank H. L. Koppens
Summary: This study reports the direct observation of in situ tunable valley-selective Hall effect and demonstrates the control of geometric phase of electrons using an out-of-plane electric field. The researchers used high-quality bilayer graphene and circularly polarized midinfrared light to observe the optically induced valley population and found a significantly larger valley-selective Hall effect compared to molybdenum disulfide. By monitoring the valley-selective Hall conductivity, the researchers studied the evolution of Berry curvature with bandgap.
Article
Materials Science, Multidisciplinary
Tirth Shah, Florian Marquardt, Vittorio Peano
Summary: The valley Hall effect is a useful method for creating stable waveguides for bosonic excitations such as photons and phonons. The absence of backscattering in many experiments is due to a smooth-envelope approximation that neglects large momentum transfer, but this accuracy is limited to small bulk band gaps and/or smooth domain walls. In experiments with larger bulk band gaps and hard domain walls, significant backscattering is expected. We demonstrate that in this relevant regime, the reflection of a wave at a sharp corner is highly sensitive to the orientation of the outgoing waveguide in relation to the underlying lattice. Enhanced backscattering occurs due to resonant tunneling transitions in quasimomentum space. Tracking the resonant tunneling energies with changes in waveguide orientation reveals a self-repeating fractal pattern that is also observed in the density of states and the backscattering rate at a sharp corner.
Article
Chemistry, Multidisciplinary
Ce Xu, Guoqing Zhou, Evgeny M. Alexeev, Alisson R. Cadore, Ioannis Paradisanos, Anna K. Ott, Giancarlo Soavi, Sefaattin Tongay, Giulio Cerullo, Andrea C. Ferrari, Oleg V. Prezhdo, Zhi-Heng Loh
Summary: Strain engineering is an effective method for tuning the local optoelectronic properties of transition metal dichalcogenides (TMDs). This study combines time-resolved photoemission electron microscopy (TR-PEEM) and nonadiabatic ab initio molecular dynamics (NAMD) to investigate the ultrafast dynamics of wrinkled multilayer (ML) MoS2. The results reveal that strain engineering can accelerate the sub-picosecond electronic relaxation dynamics of TMDs, making it a promising approach for applications requiring long-lived hot carriers.
Article
Multidisciplinary Sciences
Shinichi Nishihaya, Masaki Uchida, Yusuke Nakazawa, Markus Kriener, Yasujiro Taguchi, Masashi Kawasaki
Summary: This study demonstrates the intrinsic coupling between two spatially-separated surface states in the Weyl orbits of a Dirac semimetal film. Independent scans of top- and back-gate voltages reveal the concomitant modulation of doubly-degenerate quantum Hall states, providing new opportunities for controlling the novel quantized transport in topological semimetals.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Tong Zhou, Shuguang Cheng, Michael Schleenvoigt, Peter Schueffelgen, Hua Jiang, Zhongqin Yang, Igor Zutic
Summary: A general and tunable platform has been proposed to achieve high-density arrays of quantum spin-valley Hall kink (QSVHK) states based on a two-dimensional hexagonal topological insulator. The QSVHK states are found to be topologically protected by valley-inversion and time-reversal symmetries, with quantized conductance against disorder. These states can be realized in bismuthene through alloy engineering, surface functionalization, or electric field, supporting nonvolatile applications at room temperature.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Physical
Jiadong Zhou, Chao Zhu, Yao Zhou, Jichen Dong, Peiling Li, Zhaowei Zhang, Zhen Wang, Yung-Chang Lin, Jia Shi, Runwu Zhang, Yanzhen Zheng, Huimei Yu, Bijun Tang, Fucai Liu, Lin Wang, Liwei Liu, Gui-Bin Liu, Weida Hu, Yanfeng Gao, Haitao Yang, Weibo Gao, Li Lu, Yeliang Wang, Kazu Suenaga, Guangtong Liu, Feng Ding, Yugui Yao, Zheng Liu
Summary: This study reveals a competitive-chemical-reaction-based growth mechanism that allows for the growth of transition metal chalcogenides and transition metal phosphorous chalcogenides with different compositions and phases. It provides an interesting platform for the exploration of 2D TMPCs and TMCs.
Article
Multidisciplinary Sciences
Meizhen Huang, Zefei Wu, Jinxin Hu, Xiangbin Cai, En Li, Liheng An, Xuemeng Feng, Ziqing Ye, Nian Lin, Kam Tuen Law, Ning Wang
Summary: This study reports a significant breakthrough in the efficiency of nonlinear Hall generation in small-angle-twisted bilayer WSe2, reaching 1000 V-1, which is a hundred times higher than the previous records. The researchers explained this result through the correlation-induced continuous Mott transition effect.
NATIONAL SCIENCE REVIEW
(2023)
Article
Chemistry, Physical
Ze-Nan Hu, Yongjian Ai, Yan Zhao, Yiming Wang, Kelong Ding, Wenhui Zhang, Rongxiu Guo, Xinyue Zhang, Xiangbin Cai, Ning Wang, Jianshe Hue, Qionglin Liang, Hongyang Liu, Fei Huang, Limin Wu, Jiangwei Zhang, Hong -Bin Sung
Summary: In this study, a catalyst composed of Mo single atoms and MoO2 nanoparticles was investigated. It was found that the Mo single atoms provide the reaction zone while the MoO2 nanoparticles act as the active site. This catalyst exhibits noble metal-like catalytic activity and shows excellent performance for dechlorination-proof transfer hydrogenation.
Article
Nanoscience & Nanotechnology
Meizhen Huang, Zefei Wu, Ning Wang, Siu-Tat Chui
Summary: Coulomb drag experiments reveal anomalous behaviors in a 2D electron-electron bilayer system made of atomically thin MoS2 stacked on dielectric layers of boron nitride. The measured drag resistance deviates from the predicted behavior and increases with decreasing temperature. The phenomenon is explained by the formation of correlation-induced electron solid phases and is enhanced by the potential due to the boron nitride dielectric layers.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Multidisciplinary Sciences
Haidong Tian, Xueshi Gao, Yuxin Zhang, Shi Che, Tianyi Xu, Patrick Cheung, Kenji Watanabe, Takashi Taniguchi, Mohit Randeria, Fan Zhang, Chun Ning Lau, Marc W. Bockrath
Summary: In a flat band superconductor, the charge carriers' velocity is extremely slow, leading to peculiar superconducting behavior. Using twisted bilayer graphene, the researchers investigate the effect of the slow velocity on the superconducting state. They find evidence for small Cooper pairs and discuss the unusual nature of ultra-strong coupling superconductivity in ultra-flat Dirac bands.
Review
Multidisciplinary Sciences
Shaofan Yuan, Chao Ma, Ethan Fetaya, Thomas Mueller, Doron Naveh, Fan Zhang, Fengnian Xia
Summary: Geometry, as an ancient yet vibrant branch of mathematics, has significant and far-reaching impacts on various disciplines. In this article, we introduce a novel concept called geometric deep optical sensing, which is based on recent advancements in optical sensing and imaging. It involves the use of reconfigurable sensors to directly extract rich information from unknown incident light beams, including intensity, spectrum, polarization, spatial features, and angular momentum. We discuss the physical, mathematical, and engineering foundations of this concept, with a focus on classical and quantum geometry as well as deep neural networks. Furthermore, we explore the potential opportunities and challenges associated with this emerging scheme.
Article
Multidisciplinary Sciences
Huahui Qiu, Qicheng Zhang, Tingzhi Liu, Xiying Fan, Fan Zhang, Chunyin Qiu
Summary: Ideal acoustic metamaterials are used to construct a non-abelian braider, exploring non-abelian topological phases and phenomena in multi-gap systems.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Applied
Yongjian Luo, Changan Wang, Chao Chen, Yuan Gao, Fei Sun, Caiwen Li, Xiaozhe Yin, Chunlai Luo, Ulrich Kentsch, Xiangbin Cai, Mei Bai, Zhen Fan, Minghui Qin, Min Zeng, Jiyan Dai, Guofu Zhou, Xubing Lu, Xiaojie Lou, Shengqiang Zhou, Xingsen Gao, Deyang Chen, Jun-Ming Liu
Summary: In order to enhance energy storage density, both maximum polarization (P-max) and breakdown strength (E-b) need to be improved, even though they are inversely correlated. This study achieved order-disorder transition induced polar nanoregions in PbZrO3 thin films through low-energy ion implantation, overcoming the tradeoff between high polarizability and breakdown strength. This resulted in a tripling of the energy storage density from 20.5 to 62.3 J/cm(3) and a significant enhancement of breakdown strength. This approach can be extended to other dielectric oxides to improve energy storage performance and tailor oxide functionalities.
APPLIED PHYSICS REVIEWS
(2023)
Article
Computer Science, Interdisciplinary Applications
Gui-Bin Liu, Zeying Zhang, Zhi-Ming Yu, Yugui Yao
Summary: Motivated by easy access to complete corep data of all the 1651 magnetic space groups (MSGs) in three-dimensional space, we have developed a Mathematica package MSGCorep to provide an offline database of coreps and various functions to manipulate them. MSGCorep is the first package that is able to calculate the direct product of full coreps for any MSG and able to determine small coreps of energy bands for general purpose.
COMPUTER PHYSICS COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Ciaran Mullan, Sergey Slizovskiy, Jun Yin, Ziwei Wang, Qian Yang, Shuigang Xu, Yaping Yang, Benjamin A. A. Piot, Sheng Hu, Takashi Taniguchi, Kenji Watanabe, Kostya S. S. Novoselov, A. K. Geim, Vladimir I. I. Falko, Artem Mishchenko
Summary: Van der Waals assembly allows for the design of electronic states in 2D materials by superimposing a long-wavelength periodic potential. This twistronics approach has led to various new physics phenomena and can also be applied to tune electronic states in 3D crystals.
Article
Physics, Multidisciplinary
Meizhen Huang, Zefei Wu, Xu Zhang, Xuemeng Feng, Zishu Zhou, Shi Wang, Yong Chen, Chun Cheng, Kai Sun, Zi Yang Meng, Ning Wang
Summary: The observation of the quantum anomalous Hall effect and nonlocal transport response in twisted bilayer graphene reveals the existence of nontrivial band topology governed by Berry curvature. However, recent works have shown that nonlinear Hall signals in graphene superlattices are caused by extrinsic disorder scattering instead of intrinsic Berry curvature dipole moment. In this study, we report an intrinsic nonlinear Hall effect induced by Berry curvature dipole in high-quality twisted bilayer graphene devices. We also demonstrate that the application of the displacement field can significantly change the direction and amplitude of the nonlinear Hall voltages through a field-induced sliding of the Berry curvature hotspots. Our findings not only establish the dominant role of Berry curvature dipole in generating intrinsic nonlinear Hall signals in graphene superlattices with low disorder densities, but also highlight the potential of twisted bilayer graphene as a sensitive and fine-tunable platform for second harmonic generation and rectification.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Xiuxian Yang, Wanxiang Feng, Xiao-Ping Li, Gui-Bin Liu, Yuriy Mokrousov, Yugui Yao
Summary: Recently, unconventional anomalous electric, thermal, and thermoelectric transport properties have been observed in Heusler ferromagnets. This study investigated the mechanisms behind the anomalous Hall effect (AHE), anomalous Nernst effect (ANE), and anomalous thermal Hall effect (ATHE) in Fe2CoAl and Fe2NiAl using first-principles density functional theory calculations. It was found that disorder dominates the AHE and ATHE in Fe2CoAl, while the intrinsic Berry phase mechanism governs the AHE and ATHE in Fe2NiAl. Both intrinsic and extrinsic mechanisms contribute to the ANE in both materials. Fe2CoAl and Fe2NiAl exhibit tunable and remarkably pronounced anomalous transport properties, making them promising candidates for spintronics and spin caloritronics applications.
Article
Chemistry, Multidisciplinary
Lini Yang, Ling Li, Shuai Qin, Jingwang Zhang, Yue Wang, Xuetao Qin, Xiangbin Cai, Jiangyong Diao, Hongyang Liu
Summary: A simple and efficient strategy was developed to synthesize Pd single-atom catalysts (Pd-SA/G) using nitric acid vapor-assisted redispersion. The as-prepared Pd-SA/G exhibited robust catalytic performance in the selective hydrogenation reaction of benzaldehyde. This work opens up a new way for the design of supported Pd single-atom catalysts.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Ze-Nan Hu, Yongjian Ai, Yan Zhao, Yiming Wang, Kelong Ding, Wenhui Zhang, Rongxiu Guo, Xinyue Zhang, Xiangbin Cai, Ning Wang, Jianshe Hu, Qionglin Liang, Hongyang Liu, Fei Huang, Limin Wu, Jiangwei Zhang, Hong-Bin Sun
Summary: This study presents a catalyst composed of molybdenum single atoms and molybdenum dioxide nanoparticles, which exhibits noble metal-like catalytic activity for dechlorination-proof transfer hydrogenation. The coexistence of single atoms in nanoparticle catalysts is an important area for further research.
