Review
Chemistry, Multidisciplinary
Shan Liu, Gui Yu
Summary: The twisted bilayer graphene vdW moire superlattices exhibit exotic properties such as correlated insulating states and unconventional superconductivity, making them promising for electronic and quantum computation device manufacturing. This review discusses the fabrication, characterization, energy band engineering, and strong electronic correlation properties of vdW moire superlattices, highlighting the importance of a comprehensive understanding of these structures.
Article
Chemistry, Multidisciplinary
Zhitong Jin, Zijie Ji, Yunlei Zhong, Yunmin Jin, Xianyu Hu, Xingxing Zhang, Lijing Zhu, Xianhui Huang, Tao Li, Xinghan Cai, Lin Zhou
Summary: This study successfully synthesized high-quality and stable 2D ferromagnetic material Cr5Te8, and formed a uniform moire superlattice through heterostructures. This research provides prospects for studying the properties of non-van der Waals magnetic moire superlattices and large-scale applications that require a scalable approach.
Review
Chemistry, Physical
Jiaojiao Ma, Kaiwen Guan, Yu Jiang, Yang Cao, Sheng Hu
Summary: Research on two-dimensional materials has provided insights into the low-dimensional science and the investigation of physical and chemical processes under two-dimensional confinement. The discoveries in this field have expanded our understanding of nano-science and stimulated the development of potential applications.
Article
Materials Science, Multidisciplinary
Alexander A. Balandin, Fariborz Kargar, Tina T. Salguero, Roger K. Lake
Summary: The advent of graphene and other two-dimensional van der Waals materials has led to significant progress in fundamental science. This review focuses on the emerging field of one-dimensional van der Waals quantum materials, which involves atomic chains and their unique properties. The authors discuss various quantum effects, such as charge-density-wave condensate and topological phases, as well as the potential applications of these materials in composites.
Review
Chemistry, Multidisciplinary
Yicong Chen, Jun Chen, Zhibing Li
Summary: This article reviews the recent progress on cold cathodes with graphene as the direction, including both experimental and theoretical studies. The review emphasizes the phenomena that are absent in conventional cold cathodes but present in two-dimensional van der Waals materials, such as directionality and coherence. It also covers the fabrication of emitter structures for field emission applications, their field emission properties, and the existing field emission model.
Review
Materials Science, Multidisciplinary
Sidi Fan, Rui Cao, Lude Wang, Shan Gao, Yupeng Zhang, Xiang Yu, Han Zhang
Summary: Quantum tunneling with band-structure engineering has been successfully developed for applications in electrical, optoelectrical, and magnetic devices. Devices based on 2D van der Waals heterostructures offer superior tunneling performance and scaling down device size. The research on 2D tunneling devices is in its early stages, but they are expected to emerge as competitive candidates for low-power and high-speed devices.
SCIENCE CHINA-MATERIALS
(2021)
Article
Multidisciplinary Sciences
Long Zhang, Fengcheng Wu, Shaocong Hou, Zhe Zhang, Yu-Hsun Chou, Kenji Watanabe, Takashi Taniguchi, Stephen R. Forrest, Hui Deng
Summary: Controlling matter-light interactions with cavities is crucial in modern science and technology. By integrating MoSe2-WS2 heterobilayers in a microcavity, cooperative coupling between moire-lattice excitons and microcavity photons has been established, providing versatile control of both matter and light. This moire polariton system combines strong nonlinearity and microscopic-scale tuning of matter excitations, offering a platform to study collective phenomena from tunable arrays of quantum emitters.
Review
Chemistry, Multidisciplinary
Qing Hua Wang, Amilcar Bedoya-Pinto, Mark Blei, Avalon H. Dismukes, Assaf Hamo, Sarah Jenkins, Maciej Koperski, Yu Liu, Qi-Chao Sun, Evan J. Telford, Hyun Ho Kim, Mathias Augustin, Uri Vool, Jia-Xin Yin, Lu Hua Li, Alexey Falin, Cory R. Dean, Felix Casanova, Richard F. L. Evans, Mairbek Chshiev, Artem Mishchenko, Cedomir Petrovic, Rui He, Liuyan Zhao, Adam W. Tsen, Brian D. Gerardot, Mauro Brotons-Gisbert, Zurab Guguchia, Xavier Roy, Sefaattin Tongay, Ziwei Wang, M. Zahid Hasan, Joerg Wrachtrup, Amir Yacoby, Albert Fert, Stuart Parkin, Kostya S. Novoselov, Pengcheng Dai, Luis Balicas, Elton J. G. Santos
Summary: Research on magnetism in 2D van der Waals materials has shown exciting potential for future applications, although challenges remain. It provides important theoretical foundations and guidance for future applications.
Article
Chemistry, Physical
Jiuxiang Dai, Teng Yang, Zhitong Jin, Yunlei Zhong, Xianyu Hu, Jingyi Zou, Weigao Xu, Tao Li, Yuxuan Lin, Xu Zhang, Lin Zhou
Summary: This article reports the van der Waals epitaxy of two-dimensional indium arsenide (InAs) single crystals and investigates their thickness-dependent optical properties. The as-grown InAs flakes exhibit high crystalline quality and homogeneity, and possess high conductivity and carrier mobility in the 2D materials family, which opens up new possibilities for high-performance electronics and optoelectronics applications.
Review
Chemistry, Multidisciplinary
Yanping Liu, Cheng Zeng, Juan Yu, Jiahong Zhong, Bo Li, Zhengwei Zhang, Zongwen Liu, Zhiming M. Wang, Anlian Pan, Xidong Duan
Summary: Recent advances in moire superlattices and moire excitons have attracted attention in optoelectronics and materials research. However, lagging theoretical development and inefficient processing technologies limit their potential applications. Continued research is likely to lead to breakthroughs and innovations in solid-state physics and materials science.
CHEMICAL SOCIETY REVIEWS
(2021)
Review
Chemistry, Multidisciplinary
Haoyun Wang, Zexin Li, Dongyan Li, Ping Chen, Lejing Pi, Xing Zhou, Tianyou Zhai
Summary: This review presents recent progress in vdW integration-based infrared photodetectors, including working mechanisms and advantages of different structures, 2D/nD vdW integration, band engineering, and device performance.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Multidisciplinary Sciences
Pablo Ares, Yi Bo Wang, Colin R. Woods, James Dougherty, Laura Fumagalli, Francisco Guinea, Benny Davidovitch, Kostya S. Novoselov
Summary: Nonlinear mechanics of solids is an exciting field that involves beautiful mathematics, instabilities, complex patterns, and various applications. By studying the formation of wrinkles in two-dimensional crystals and van der Waals heterostructures, researchers can gain finer control over parameters and offer atomistic interpretations of experimental observations. The relationship between the bending rigidity of the top membrane and the strength of the vdW interaction is shown to influence the number of radial wrinkles, demonstrating a nontrivial dependence on the number of layers and the alignment between the substrate and the membrane.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Review
Chemistry, Multidisciplinary
Liping Liao, Evgeniya Kovalska, Jakub Regner, Qunliang Song, Zdenek Sofer
Summary: This review paper analyzes the use of van der Waals thin films derived from 2D materials in the advancement of thin-film electronics and optoelectronic devices. It highlights the superior properties and stability of inorganic nanomaterials that can be solution-processed, emphasizing the importance of solution-based processing. The challenges and potential of scalable 2D vdW thin films in driving advancements in electronics and optoelectronics are discussed.
Article
Nanoscience & Nanotechnology
N. Sarkar, P. R. Bandaru, R. C. Dynes
Summary: A methodology for testing the interlayer bonding strength of 2D surfaces and associated 1D and 2D surface defects using scanning tunneling microscope tip-induced deformation is demonstrated. The surface elastic deformation characteristics of soft 2D monatomic sheets such as graphene and graphite are found to be related to the underlying local bonding configurations. The surface deformation of 2D graphitic moire patterns reveals the varying inter-layer van der Waals strength across its domains. These findings contribute to the understanding of interlayer bonding strength in 1D grain boundaries and grains, as well as anomalous phenomena in probing 2D materials at small gap distances as a function of strain.
Article
Chemistry, Multidisciplinary
Hsun-Jen Chuang, Madeleine Phillips, Kathleen M. McCreary, Darshana Wickramaratne, Matthew R. Rosenberger, Vladimir P. Oleshko, Nicholas Proscia, Mark Lohmann, Dante J. O'Hara, Paul D. Cunningham, C. Stephen Hellberg, Berend T. Jonker
Summary: The appearance of moire Raman modes from nearly aligned WSe2-WS2 van der Waals heterostructures in a certain frequency range indicates sensitivity to twist angle and strong Raman intensity modulation dependent on excitation energy and temperature. These modes exhibit identical frequencies for a given small twist angle and are a consequence of the large moire length scale resulting in zone-folded phonon modes that are Raman active.
Article
Nanoscience & Nanotechnology
Yoshitaka Shingaya, Amir Zulkefli, Takuya Iwasaki, Ryoma Hayakawa, Shu Nakaharai, Kenji Watanabe, Takashi Taniguchi, Yutaka Wakayama
Summary: This paper presents a dual-gate anti-ambipolar transistor (AAT) with a two-dimensional ReS2 and WSe2 heterojunction, where the characteristic ?-shaped transfer curves controlled by the top-gate voltage effectively control the bottom-gate voltage. This feature is applied to logic operations, allowing the AAT to perform all two-input logic operations under optimized input voltages and achieve switching between AND and OR logic operations induced by the drain voltage.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Physics, Applied
Xingzhou Chen, Zheng Sun, Min Zhang, Ming Li, Zhigao Hu, Kenji Watanabe, Takashi Taniguchi, David Snoke, Zhe-Yu Shi, Jian Wu
Summary: We have designed and fabricated a vertical structure using a distributed Bragg reflector and dielectric material layer to enhance optical absorption in a stack of monolayer WS2 and MoS2. Our research shows a tenfold increase in absorption over a 100 nm spectral range, with the potential to achieve over 50% absorption by tuning the spacer layer thickness. Our theoretical model explains the dependence of absorption coefficient on spacer thickness as a solution of a non-Hermitian Schrodinger equation. These findings contribute to the development of broadband optical devices utilizing two-dimensional excitonic materials.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Yihang Zeng, Zhengchao Xia, Roei Dery, Kenji Watanabe, Takashi Taniguchi, Jie Shan, Kin Fai Mak
Summary: In a heterostructure composed of WS2/bilayer WSe2/WS2 multilayers, it was discovered that strongly correlated bosons can be trapped in a triangular lattice. Correlated insulating states were observed when the electron filling factor of the two lattices reached 1/3, 2/3, 4/3, and 5/3. These states can be explained as exciton density waves in a Bose-Fermi mixture of excitons and holes. The strong repulsive interactions between the constituents led to the formation of robust generalized Wigner crystals, which restricted the exciton fluid to channels that spontaneously broke the translational symmetry of the lattice. These results demonstrate that Coulomb-coupled lattices are a fertile ground for studying correlated many-boson phenomena.
Article
Chemistry, Multidisciplinary
Matthew S. G. Feuer, Alejandro R. -P. Montblanch, Mohammed Y. Sayyad, Carola M. Purser, Ying Qin, Evgeny M. Alexeev, Alisson R. Cadore, Barbara L. T. Rosa, James Kerfoot, Elaheh Mostaani, Radoslaw Kaleba, Pranvera Kolari, Jan Kopaczek, Kenji Watanabe, Takashi Taniguchi, Andrea C. Ferrari, Dhiren M. Kara, Sefaattin Tongay, Mete Atature
Summary: Janus transition-metal dichalcogenide monolayers are artificial materials with unique properties, such as long-lived, dipolar excitons and direct-band gap optical transitions. In this study, the specific excitonic origin of Janus WSe S monolayers with narrow optical line widths is identified. The integration of Janus monolayers into vertical heterostructures allows for doping control and the development of optoelectronic devices. These findings have important implications for nanoscale sensing and the advancement of Janus-based technology.
Article
Chemistry, Multidisciplinary
Jinpeng Tian, Qinqin Wang, Xudan Huang, Jian Tang, Yanbang Chu, Shuopei Wang, Cheng Shen, Yancong Zhao, Na Li, Jieying Liu, Yiru Ji, Biying Huang, Yalin Peng, Rong Yang, Wei Yang, Kenji Watanabe, Takashi Taniguchi, Xuedong Bai, Dongxia Shi, Luojun Du, Guangyu Zhang
Summary: This study presents a self-encapsulated heterostructure undercut technique for fabricating sub-10 nm channel length MoS2 FETs. The 9 nm channel MoS2 FETs fabricated using this technique exhibit superior performances and excellent homogeneity.
Article
Chemistry, Physical
Jian-Xiang Qiu, Christian Tzschaschel, Junyeong Ahn, Anyuan Gao, Houchen Li, Xin-Yue Zhang, Barun Ghosh, Chaowei Hu, Yu-Xuan Wang, Yu-Fei Liu, Damien Berube, Thao Dinh, Zhenhao Gong, Shang-Wei Lien, Sheng-Chin Ho, Bahadur Singh, Kenji Watanabe, Takashi Taniguchi, David C. Bell, Hai-Zhou Lu, Arun Bansil, Hsin Lin, Tay-Rong Chang, Brian B. Zhou, Qiong Ma, Ashvin Vishwanath, Ni Ni, Su-Yang Xu
Summary: Using circularly polarized light, researchers have observed helicity-dependent optical control of fully compensated antiferromagnetic order in a topological axion insulator called MnBi2Te4. This optical control and circular dichroism are based on the optical axion electrodynamics and can potentially be used to control PT-symmetric antiferromagnets and create dissipationless circuits using topological edge states.
Article
Multidisciplinary Sciences
Pingfan Gu, Cong Wang, Dan Su, Zehao Dong, Qiuyuan Wang, Zheng Han, Kenji Watanabe, Takashi Taniguchi, Wei Ji, Young Sun, Yu Ye
Summary: The authors demonstrate a magnetoelectric effect in a van der Waals antiferromagnetic CrOCl material, which allows for multi-state data storage. This material shows promise for new data storage technologies with low power consumption, functionality, and high energy efficiency.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Di Huang, Kevin Sampson, Yue Ni, Zhida Liu, Danfu Liang, Kenji Watanabe, Takashi Taniguchi, Hebin Li, Eric Martin, Jesper Levinsen, Meera M. Parish, Emanuel Tutuc, Dmitry K. Efimkin, Xiaoqin Li
Summary: When mobile impurities are introduced and coupled to a Fermi sea, new quasiparticles called Fermi polarons are formed. There are two regimes of the Fermi polaron problem: attractive polarons (AP) connected to pairing phenomena, and repulsive polarons (RP) responsible for ferromagnetism. In this study, we investigate Fermi polarons in a doped MoSe2 monolayer and find agreement with polaron theory for attractive polarons. The dynamics of Fermi polarons are important for understanding pairing and magnetic instabilities in various physical systems.
Article
Nanoscience & Nanotechnology
Dong Hoon Shin, Duk Hyun Lee, Sang-Jun Choi, Seonyeong Kim, Hakseong Kim, Kenji Watanabe, Takashi Taniguchi, Eleanor E. B. Campbell, Sang Wook Lee, Suyong Jung
Summary: Weak interlayer couplings at 2D van der Waals interfaces fundamentally distinguish out-of-plane charge flow, the information carrier in vdW-assembled vertical electronic and optical devices, from the in-plane band transport processes. The out-of-plane charge transport behavior in 2D van der Waals semiconducting transition metal dichalcogenides (SCTMD) is studied and it is found that Fowler-Nordheim tunneling becomes the dominant quantum transport process in ultrathin SCTMDs, down to monolayers, in the high electric field regime, especially at low temperatures. The sequential layer-by-layer FN tunneling is observed to dominate the charge flow in few-layer SCTMDs, providing insight into the Fermi level positions and layer numbers of the SCTMD films.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yueh-Chun Wu, Takashi Taniguchi, Kenji Watanabe, Jun Yan
Summary: Monolayer transition metal dichalcogenide semiconductors are promising valleytronic materials, and the valley polarized holes are particularly interesting due to their long valley lifetime preserved by the large spin-orbit splitting and spin-valley locking.
Article
Chemistry, Multidisciplinary
Priya Tiwari, Divya Sahani, Atasi Chakraborty, Kamal Das, Kenji Watanabe, Takashi Taniguchi, Amit Agarwal, Aveek Bid
Summary: In this study, the experimental evidence of the time-reversal symmetric Hall effect in high-mobility graphene-WSe2 heterostructures is provided. This dissipative Hall effect is linear and its sign depends on the charge carriers. It persists up to room temperature and can be tuned using an external electric field. The strain induced by lattice mismatch or alignment angle inhomogeneity breaks the inversion symmetry and produces anisotropic bands in graphene, leading to the appearance of a time-reversal symmetric Hall effect.
Article
Multidisciplinary Sciences
Dacen Waters, Ellis Thompson, Esmeralda Arreguin-Martinez, Manato Fujimoto, Yafei Ren, Kenji Watanabe, Takashi Taniguchi, Ting Cao, Di Xiao, Matthew Yankowitz
Summary: Moire patterns formed by stacking twisted atomically thin van der Waals crystals can modify the electronic properties of bulk graphitic thin films in a dual-gated device. At zero and small magnetic fields, transport is mediated by gate-tuneable moire and graphite surface states, as well as coexisting semimetallic bulk states. At high field, the moire potential hybridizes with the graphitic bulk states, creating a single quasi-two-dimensional hybrid structure. This study establishes twisted graphene-graphite as a new class of mixed-dimensional moire materials.
Article
Physics, Multidisciplinary
Gelareh Farahi, Cheng-Li Chiu, Xiaomeng Liu, Zlatko Papic, Kenji Watanabe, Takashi Taniguchi, Michael P. P. Zaletel, Ali Yazdani
Summary: We demonstrate a non-invasive spectroscopic technique with a scanning tunnelling microscope, which allows us to investigate the broken-symmetry states and excitation spectrum of the partially filled zeroth Landau level in graphene. Our experimental approach quantifies the interacting phase diagram of the zeroth Landau level and provides insights into the repulsive interactions underlying the fractional quantum states.
Article
Chemistry, Multidisciplinary
Karolina Ewa Polczynska, Simon Le Denmat, Takashi Taniguchi, Kenji Watanabe, Marek Potemski, Piotr Kossacki, Wojciech Pacuski, Jacek Kasprzak
Summary: Using four-wave mixing microscopy, the coherent response and ultrafast dynamics of excitons and trions in MoSe2 monolayers grown by molecular beam epitaxy on thin films of hexagonal boron nitride are measured. The inhomogeneous and homogeneous broadenings in the transition spectral lineshape are evaluated. The impact of phonons on the homogeneous dephasing is inferred through the temperature dependence of the dephasing. Four-wave mixing mapping combined with atomic force microscopy reveals spatial correlations between exciton oscillator strength, inhomogeneous broadening, and the sample morphology. The quality of the coherent optical response of epitaxially grown transition metal dichalcogenides is now comparable to mechanically exfoliated samples, enabling the coherent nonlinear spectroscopy of innovative materials such as magnetic layers or Janus semiconductors.
Article
Nanoscience & Nanotechnology
Kai Liu, Jian Zheng, Yating Sha, Bosai Lyu, Fengping Li, Youngju Park, Yulu Ren, Kenji Watanabe, Takashi Taniguchi, Jinfeng Jia, Weidong Luo, Zhiwen Shi, Jeil Jung, Guorui Chen
Summary: Interactions among charge carriers in graphene can lead to the spontaneous breaking of multiple degeneracies. In this study, the stacking orders of tetralayer graphene devices were determined using near-field infrared imaging. Through quantum transport measurements, a range of spontaneous broken-symmetry states and their transitions were observed, which could be finely tuned by carrier density and electric displacement field. These findings highlight the potential of multilayer graphene as a platform for investigating broken symmetries.
NATURE NANOTECHNOLOGY
(2023)