Article
Chemistry, Multidisciplinary
Dmitry Roshchupkin, Oleg Kononenko, Rashid Fakhrtdinov, Evgenii Emelin, Alexander Sergeev
Summary: This study investigates the acoustically stimulated charge transport in graphene film on the LiNbO3 crystal surface. The results show a linear relationship between the current in the graphene film and the frequency of the surface acoustic wave (SAW) excitation. Additionally, changing the amplitude of the SAW can alter the direction of the current in the graphene film. In a specific frequency range, the current can change from positive to negative values depending on the frequency. Therefore, by controlling the SAW excitation frequency and amplitude, it is possible to manipulate the current in the graphene film.
Article
Multidisciplinary Sciences
Alexander Kerelsky, Carmen Rubio-Verdu, Lede Xian, Dante M. Kennes, Dorri Halbertal, Nathan Finney, Larry Song, Simon Turkel, Lei Wang, Kenji Watanabe, Takashi Taniguchi, James Hone, Cory Dean, Dmitri N. Basov, Angel Rubio, Abhay N. Pasupathy
Summary: This study demonstrates the formation of emergent correlated phases in multilayer rhombohedral graphene without the need for twisted van der Waals layers. The study shows that two layers of bilayer graphene twisted by a tiny angle can host large regions of uniform rhombohedral four-layer graphene with a sharp van Hove singularity. Furthermore, the study suggests that the broken symmetry state in ABCA graphene could be attributed to a charge-transfer excitonic insulator or a ferrimagnet.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Multidisciplinary Sciences
Zachary J. Krebs, Wyatt A. Behn, Songci Li, Keenan J. Smith, Kenji Watanabe, Takashi Taniguchi, Alex Levchenko, Victor W. Brar
Summary: In this study, we used scanning tunneling potentiometry to investigate the nanometer-scale flow of electron fluids in graphene. We observed a transition from ballistic to viscous flow regime as the temperature and channel widths increased.
Article
Nanoscience & Nanotechnology
Liang Cao, Ri Liu, Wenxiao Zhang, Ying Wang, Guoliang Wang, Zhengxun Song, Zhankun Weng, Zuobin Wang
Summary: In this study, a novel functional nanoprobe is presented using graphene sheets in a high-quality graphene solution wrapped round a plasma-treated conventional Pt-Ir coated nanoprobe. The graphene-wrapped nanoprobes show highly stability and resistance to degradation, leading to a significantly increased lifetime. Furthermore, they exhibit enhanced electrical conductivity and reduced tip-sample friction compared with Pt-Ir coated nanoprobes.
Article
Chemistry, Multidisciplinary
Wei Nie, Qianhong Zhu, Yuying Gao, Ziyuan Wang, Yong Liu, Xun Wang, Ruotian Chen, Fengtao Fan, Can Li
Summary: The study reveals locally enhanced electron transfer (ET) current at corner sites on single Au triangular nanoplates due to mass transport effect, showing a 2-fold increase in ET rate constant compared to basal {111} plane. Additionally, the spatial heterogeneity of local inner potential differences at Au nanoplates/solution interfaces is found to play a key role in the ET process.
Article
Multidisciplinary Sciences
Rama Krishnan Vasudevan, Sai Mani Valleti, Maxim Ziatdinov, Gerd Duscher, Suhas Somnath
Summary: Major advancements in various fields have relied on microscopy techniques, but there are still significant challenges in processing and analyzing the acquired datasets. The pycroscopy ecosystem introduces a common data model and leverages Python-based packages to accelerate analysis and visualization, enabling the creation of reproducible workflows for microscopy data.
ADVANCED THEORY AND SIMULATIONS
(2023)
Article
Materials Science, Multidisciplinary
Ke Wang, T. A. Sedrakyan
Summary: Perpendicular magnetic field introduces an anomalous interaction correction to the static conductivity of doped graphene, leading to a proportional relationship between magnetoresistance and inverse temperature. This behavior originates from field-induced breaking of symmetry.
Article
Chemistry, Multidisciplinary
Remy Pawlak, Xunshan Liu, Silviya Ninova, Philipp D'Astolfo, Carl Drechsel, Jung-Ching Liu, Robert Haner, Silvio Decurtins, Ulrich Aschauer, Shi-Xia Liu, Ernst Meyer
Summary: In this study, a substrate-assisted reaction on Ag(111) was used to synthesize two-dimensional graphene sheets with a long-range honeycomb Kagome lattice. Low-temperature scanning tunneling microscopy and atomic force microscopy, supported by density functional theory, were employed to scrutinize the structural and electronic properties of N-KG down to the atomic scale. The research demonstrated the semiconducting character of N-KG due to nitrogen doping, as well as the emergence of Kagome flat bands near the Fermi level.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Kirill A. Bokai, Viktor O. Shevelev, Dmitry Marchenko, Anna A. Makarova, Vladimir Yu Mikhailovskii, Alexei A. Zakharov, Oleg Yu Vilkov, Maxim Krivenkov, Denis V. Vyalikh, Dmitry Yu Usachov
Summary: Intercalation of oxygen can facilitate the detection of grain boundaries in polycrystalline graphene, providing insights into their morphology, and enabling visualization through various electron microscopy methods.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Junxi Yu, Rajiv Giridharagopal, Yuhao Li, Kaichen Xie, Jiangyu Li, Ting Cao, Xiaodong Xu, David S. Ginger
Summary: By studying graphene with ABAB and ABCA stacking, it was found that the surface potential of ABCA regions is approximately 15 mV higher than that of ABAB regions, due to stacking-dependent electronic structure. The moire superlattice visualized by LPFM can change with time, while imaging the surface potential distribution via SKPM appears more stable for mapping ABAB and ABCA regions.
Article
Chemistry, Multidisciplinary
Boris Brun, Viet-Hung Nguyen, Nicolas Moreau, Sowmya Somanchi, Kenji Watanabe, Takashi Taniguchi, Jean-Christophe Charlier, Christoph Stampfer, Benoit Hackens
Summary: When confined in circular cavities, graphene charge carriers occupy whispering gallery modes (WGMs) similarly to classical acoustic and optical fields. The study successfully demonstrated the transduction of WGMs to the outside world through a novel configuration, showing mode selectivity and potential for designing disruptive quantum devices. This work provides a proof of concept for graphene whisperitronic devices.
Article
Chemistry, Multidisciplinary
Alejandro Berdonces-Layunta, James Lawrence, Shayan Edalatmanesh, Jesus Castro-Esteban, Tao Wang, Mohammed S. G. Mohammed, Luciano Colazzo, Diego Pena, Pavel Jelinek, Dimas G. de Oteyza
Summary: Nanostructured graphene has been widely studied in recent years due to its tunable electronic properties for various fields. However, exposure of (3,1)-chiral graphene nanoribbons to oxidizing environments significantly oxidizes the ribbons and disrupts their electronic properties. Experiments show that even under gentle conditions, the ribbons are oxidized, providing insights into the reaction sites and defects caused by oxygen.
Article
Nanoscience & Nanotechnology
Hesham El-Sherif, Natalie Briggs, Brian Bersch, Minghao Pan, Mahdi Hamidinejad, Siavash Rajabpour, Tobin Filleter, Ki Wook Kim, Joshua Robinson, Nabil D. Bassim
Summary: In this study, the thickness of 2D-Ga heterostructures was resolved and measured using scanning electron microscopy (SEM), with the SEM image contrast directly related to the presence of uniform bilayer Ga at the interface and variation of graphene layers. By utilizing multiple correlative methods, the researchers investigated the origin of SEM contrast and found that a carbon buffer layer detached due to gallium intercalation, increasing the surface potential as an indication of the 2D-Ga presence. The study also successfully scaled up heterostructure characterization over a few-square millimeter area by segmenting SEM images with nanometer-scale in-plane resolution, leveraging the spectroscopic imaging capabilities of SEM for tracking intercalants, identifying relative surface potentials, determining the number of 2D layers, and further characterizing scalability and uniformity of low-dimensional materials.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Jincan Zhang, Kaicheng Jia, Yongfeng Huang, Xiaoting Liu, Qiuhao Xu, Wendong Wang, Rui Zhang, Bingyao Liu, Liming Zheng, Heng Chen, Peng Gao, Sheng Meng, Li Lin, Hailin Peng, Zhongfan Liu
Summary: The study found that pristine graphene exhibits high hydrophilicity with an average water contact angle of approximately 30 degrees, due to charge transfer between graphene and water molecules. This work provides insight into water-graphene interaction and introduces a new approach for measuring surface properties of 2D materials.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Yuhiro Segawa, Kenji Yamazaki, Jun Yamasaki, Kazutoshi Gohara
Summary: A new method for measuring the 3D atomic structure of free-standing graphene ripples using TEM is proposed and experimentally validated. The specimen in the experiment was found to be moving upward, and the ripple was approximated as a composite of sinusoidal waves while measuring the time dependence of its height and lateral size.
Article
Chemistry, Multidisciplinary
Sai S. Sunku, Dorri Halbertal, Rebecca Engelke, Hyobin Yoo, Nathan R. Finney, Nicola Curreli, Guangxin Ni, Cheng Tan, Alexander S. McLeod, Chiu Fan Bowen Lo, Cory R. Dean, James C. Hone, Philip Kim, D. N. Basov
Summary: Graphene-based heterostructures present a variety of phenomena tunable by electrostatic local gates. While monolayer graphene exhibits tunable surface plasmon polaritons, bilayer graphene may display unique plasmonic effects such as plasmon amplification and domain wall plasmons. These effects are highly sensitive to displacement fields and have potential applications in nano-optics.
Article
Nanoscience & Nanotechnology
Yuval Ronen, Thomas Werkmeister, Danial Haie Najafabadi, Andrew T. Pierce, Laurel E. Anderson, Young Jae Shin, Si Young Lee, Young Hee Lee, Bobae Johnson, Kenji Watanabe, Takashi Taniguchi, Amir Yacoby, Philip Kim
Summary: Interferometers probe the wave-nature and exchange statistics of indistinguishable particles, enabling the observation and control of FQHE through graphene-based interferometers. Graphite-encapsulated architectures establish vdW heterostructures as a versatile alternative to GaAs-based interferometers for experiments targeting anyonic quasi-particles.
NATURE NANOTECHNOLOGY
(2021)
Article
Multidisciplinary Sciences
Zeyu Hao, A. M. Zimmerman, Patrick Ledwith, Eslam Khalaf, Danial Haie Najafabadi, Kenji Watanabe, Takashi Taniguchi, Ashvin Vishwanath, Philip Kim
Summary: By constructing a van der Waals heterostructure with three stacked graphene layers at alternating twist angles, researchers observed tunable superconductivity at a specific twist angle. The superconducting regions are associated with flavor polarization of moire bands and are bounded by a van Hove singularity at high displacement fields, indicating unconventional moire superconductivity.
Article
Chemistry, Multidisciplinary
Hana Yoon, Mehdi Rezaee, Yeong A. Lee, Kanghoon Yim, Rizcky Tamarany, Chan-Woo Lee, Valerie S. McGraw, Takashi Taniguchi, Kenji Watanabe, Philip Kim, Chung-Yul Yoo, D. Kwabena Bediako
Summary: In this study, the energetics and dynamics of chloroaluminate ion intercalation in a rechargeable aluminum-ion battery were investigated. The results demonstrate that engineering ion transport can lead to significant improvements in battery performance.
Article
Nanoscience & Nanotechnology
Jonah Waissman, Laurel E. Anderson, Artem Talanov, Zhongying Yan, Young J. Shin, Danial H. Najafabadi, Mehdi Rezaee, Xiaowen Feng, Daniel G. Nocera, Takashi Taniguchi, Kenji Watanabe, Brian Skinner, Konstantin A. Matveev, Philip Kim
Summary: The combination of reduced dimensionality, strong interactions, and topology in low-dimensional systems leads to many-body quantum phenomena. Thermal transport serves as a discriminating probe in quantum materials and devices, with the need for experimental methods to isolate electronic contributions. Measurements using noise thermometers and linear and nonlinear thermal transport reveal signatures of energy transport mediated by long-range interactions in one-dimensional electron systems.
NATURE NANOTECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Xiaomeng Liu, J. I. A. Li, Kenji Watanabe, Takashi Taniguchi, James Hone, Bertrand Halperin, Philip Kim, Cory R. Dean
Summary: We have studied the transition between two bosonic quantum condensate phases in a solid-state system using magneto-exciton condensates in graphene double layers.
Article
Multidisciplinary Sciences
Ko-Fan Huang, Yuval Ronen, Regis Melin, Denis Feinberg, Kenji Watanabe, Takashi Taniguchi, Philip Kim
Summary: In this study, the authors measured the interference effects of Cooper Quartets in a multi-terminal graphene Josephson junction and provided evidence for interference between different quartet processes. The experimental results showed periodic variations in the quartet differential conductance associated with charge and the behavior of the critical current can be modeled by transitions between Floquet-ABSs. This observation extends our understanding of multi-terminal Josephson junctions and paves the way for the future design of topologically unique ABS spectra.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Trond Andersen, Ryan J. Gelly, Giovanni Scuri, Bo L. Dwyer, Dominik S. Wild, Rivka Bekenstein, Andrey Sushko, Jiho Sung, You Zhou, Alexander A. Zibrov, Xiaoling Liu, Andrew Y. Joe, Kenji Watanabe, Takashi Taniguchi, Susanne F. Yelin, Philip Kim, Hongkun Park, Mikhail D. Lukin
Summary: Techniques to control the flow of light on subwavelength scales enable new optical systems and device applications. This study demonstrates a few-pixel beam steering device based on electrostatic gate control of excitons in an atomically thin semiconductor with strong light-matter interactions. The device achieves continuously tunable beam deflection, two-dimensional beam steering, and fast switching times down to 1.6 nanoseconds. This opens possibilities for atomically thin optical systems with rapidly switchable beam arrays and quantum metasurfaces.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Onder Gul, Yuval Ronen, Si Young Lee, Hassan Shapourian, Jonathan Zauberman, Young Hee Lee, Kenji Watanabe, Takashi Taniguchi, Ashvin Vishwanath, Amir Yacoby, Philip Kim
Summary: Researchers have successfully constructed graphene-based van der Waals devices with narrow superconducting niobium nitride (NbN) electrodes. The study reveals the coexistence of superconductivity and a robust fractional quantum Hall (FQH) state in these devices. Additionally, the study identifies a possible signature for crossed Andreev reflection (CAR) across the superconductor, separating two FQH edges.
Article
Chemistry, Multidisciplinary
Yeonchoo Cho, Gabriel R. Schleder, Daniel T. Larson, Elise Brutschea, Kyung-Eun Byun, Hongkun Park, Philip Kim, Efthimios Kaxiras
Summary: The researchers propose a solution to the metal-semiconductor contact resistance problem, called modulation doping, by placing a doping layer on the opposite side of the metal-semiconductor interface. By using first-principles calculations, they demonstrate that modulation doping can reduce the Schottky barrier height and contact resistance at the metal-semiconductor interface. The feasibility of this approach is demonstrated for single-layer tungsten diselenide and 2D MXene materials, and it can be generalized for other 2D semiconductors.
Article
Multidisciplinary Sciences
Elena Meirzadeh, Austin M. Evans, Mehdi Rezaee, Milena Milich, Connor J. Dionne, Thomas P. Darlington, Si Tong Bao, Amymarie K. Bartholomew, Taketo Handa, Daniel J. Rizzo, Ren A. Wiscons, Mahniz Reza, Amirali Zangiabadi, Natalie Fardian-Melamed, Andrew C. Crowther, P. James Schuck, D. N. Basov, Xiaoyang Zhu, Ashutosh Giri, Patrick E. Hopkins, Philip Kim, Michael L. Steigerwald, Jingjing Yang, Colin Nuckolls, Xavier Roy
Summary: This study introduces a two-dimensional crystalline polymer called graphullerene, which bridges the gap between molecular and extended carbon materials. It consists of hexagonally arranged C60 fullerene subunits that are covalently interconnected. The researchers have successfully synthesized large, charge-neutral, purely carbon-based crystals that can be mechanically exfoliated to produce molecularly thin flakes with clean interfaces. The thermal conductivity of graphullerene is found to be higher than that of molecular C60, thanks to its in-plane covalent bonding. Furthermore, the presence of moire-like superlattices is observed using transmission electron microscopy and near field nano-photoluminescence spectroscopy.
Article
Nanoscience & Nanotechnology
Yue Luo, Nannan Mao, Dapeng Ding, Ming-Hui Chiu, Xiang Ji, Kenji Watanabe, Takashi Taniguchi, Vincent Tung, Hongkun Park, Philip Kim, Jing Kong, William L. Wilson
Summary: In-plane anisotropic exciton-polariton propagation in SnSe allows for nanoscale imaging of in-plane ferroelectric domains. The control and manipulation of exciton-polaritons in two-dimensional quantum materials has the potential for nanoscale control of electromagnetic fields. By studying the propagation dynamics and dispersion of exciton-polaritons in SnSe, a group-IV monochalcogenide semiconductor, it was found that this propagation enables imaging of the in-plane ferroelectric domains. Additionally, electric switching of exciton-polaritons in the ferroelectric domains of this complex van der Waals system was demonstrated, suggesting the potential for reconfigurable polaritonic optical devices.
NATURE NANOTECHNOLOGY
(2023)
Article
Engineering, Multidisciplinary
Paul Cazeaux, Drake Clark, Rebecca Engelke, Philip Kim, Mitchell Luskin
Summary: Moire patterns result from the twist angle of 2D materials or the lattice mismatch of 2D heterostructures. We propose a continuum model to describe the elastic energy of bilayer moire structures, including both intralayer and interlayer energies. The displacement field that minimizes the global elastic energy subject to a global boundary constraint leads to alternating regions of two energy-minimizing stackings separated by domain walls. We derive a model for the domain wall structure and provide an improved estimate for the gradient norm in twisted bilayers.
JOURNAL OF ELASTICITY
(2023)
Article
Chemistry, Multidisciplinary
Eun Hye Kim, Do Hee Lee, Tae Jun Gu, Hyobin Yoo, Yamujin Jang, Jaemo Jeong, Hyun-Woo Kim, Seog-Gyun Kang, Hoijoon Kim, Heesoo Lee, Kyu-Jin Jo, Beom Ju Kim, Jin Wook Kim, Seong Hyun Im, Chang Seok Oh, Changgu Lee, Ki Kang Kim, Cheol-Woong Yang, Hyoungsub Kim, Youngkuk Kim, Philip Kim, Dongmok Whang, Joung Real Ahn
Summary: Replacing silicon dioxide (SiO2) with a single crystal silicon oxynitride (SiON) layer can enhance the electron mobility of 2D materials. The SiON layer can be grown at a wafer scale on a SiC substrate through a single thermal process, making it compatible with commercial semiconductor fabrication processes.
Article
Materials Science, Multidisciplinary
Rebecca Engelke, Hyobin Yoo, Stephen Carr, Kevin Xu, Paul Cazeaux, Richard Allen, Andres Mier Valdivia, Mitchell Luskin, Efthimios Kaxiras, Minhyong Kim, Jung Hoon Han, Philip Kim
Summary: In this study, practical and analytical tools are developed to understand the nano-scale moire superlattice structure, which can be applied to other lattice distortions and lattice types. It is found that at large enough moire lengths, all moire systems relax into commensurated 2D domains separated by networks of dislocation lines. These dislocation line networks can be considered as vortexlike topological defects.
