Article
Multidisciplinary Sciences
Wenjin Zhao, Bowen Shen, Zui Tao, Zhongdong Han, Kaifei Kang, Kenji Watanabe, Takashi Taniguchi, Kin Fai Mak, Jie Shan
Summary: Scientists have realized synthetic Kondo lattice in AB-stacked MoTe2/WSe2 moire bilayers, observing heavy fermions and demonstrating gate-tunable Kondo temperatures. This study opens the possibility of accessing the phase diagram of the Kondo lattice using semiconductor moire materials.
Article
Physics, Multidisciplinary
Jiacheng Zhu, Tingxin Li, Andrea F. Young, Jie Shan, Kin Fai Mak
Summary: This study demonstrates a mechanism for magnetoresistance oscillations in insulating states of 2D materials, showing that the oscillations are correlated with the high-density Fermi surface and due to the oscillatory behavior of graphite density of states. This unified mechanism for quantum oscillations in graphite-gated 2D insulators is based on electrostatic sample-gate coupling.
PHYSICAL REVIEW LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Shen Zhao, Zhijie Li, Xin Huang, Anna Rupp, Jonas Goeser, Ilia A. Vovk, Stanislav Yu. Kruchinin, Kenji Watanabe, Takashi Taniguchi, Ismail Bilgin, Anvar S. Baimuratov, Alexander Hoegele
Summary: Moire effects in vertically stacked 2D crystals can lead to new quantum materials with rich transport and optical phenomena. However, due to finite elasticity, the superlattices can transform into periodically reconstructed patterns. In this study, the concept of lattice reconstruction is expanded to the mesoscopic scale, and its consequences in optical studies of excitons in MoSe2-WSe2 heterostructures are demonstrated.
NATURE NANOTECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Seung Gyo Jeong, Jihyun Kim, Taewon Min, Sehwan Song, Jin Young Oh, Woo-suk Noh, Sungkyun Park, Tuson Park, Jong Mok Ok, Jaekwang Lee, Woo Seok Choi
Summary: The modulation of magnetic anisotropy near a digitized dimensional Mott boundary in artificial superlattices composed of SrRuO3 and SrTiO3 is demonstrated. The interlayer coupling strength between the magnetic monolayers is initially engineered, leading to a nearly degenerate state where the anisotropic magnetotransport is strongly influenced by thermal and magnetic energy scales. These findings provide a new approach for digitally controlling magnetic anisotropy in low-dimensional Mott systems, inspiring integration of Mottronics and spintronics.
Article
Nanoscience & Nanotechnology
Yang Xu, Kaifei Kang, Kenji Watanabe, Takashi Taniguchi, Kin Fai Mak, Jie Shan
Summary: Twisting the AB-homobilayer of WSe2 enables the realization of bilayer Hubbard model in the weak interlayer hopping limit, leading to observation of competing electronic states transition.
NATURE NANOTECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
I Vergara, M. Magnaterra, P. Warzanowski, J. Attig, S. Kunkemoeller, D. Khomskii, M. Braden, M. Hermanns, M. Grueninger
Summary: This article discusses the competition between spin-orbit coupling and crystal field splitting in Ca2RuO4, and explains the orbital occupation ratio using optical spectral weights. The study shows that Δ(CF)/ζ is between 2.4 and 4 at 15 K. The crystal field dominates the orbital order of the ground state, but spin-orbit coupling is necessary for a quantitative description of the properties. Furthermore, the crystal field splitting decreases with increasing temperature.
Article
Physics, Multidisciplinary
Dongxue Chen, Zhen Lian, Xiong Huang, Ying Su, Mina Rashetnia, Lei Ma, Li Yan, Mark Blei, Li Xiang, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Dmitry Smirnov, Zenghui Wang, Chuanwei Zhang, Yong-Tao Cui, Su-Fei Shi
Summary: This paper reports the observation of an excitonic insulator in an angle-aligned monolayer WS2/bilayer WSe2 moire superlattice. By tuning the valence band in the second WSe2 layer to overlap with the moire miniband in the first WSe2 layer, the coexistence of electrons and holes is achieved, resulting in the formation of an excitonic insulator with a high transition temperature.
Article
Materials Science, Multidisciplinary
Hao-Yu Niu, Xiong He, Zhuo Zeng, Yu-Jie Song, De-Quan Jiang, Hao Huang, You-Yuan Liang, Li-Xia Xiao, Zhong-Wen Ouyang, Zheng-Cai Xia
Summary: The in-plane magnetoresistance and magnetostriction of Ca3Ru2O7 single crystals were studied under pulsed magnetic field. Field-induced resistance steps and structural change were observed, which were not observed under static magnetic field. These results reveal the existence of instantaneous interactions among different degrees of freedom in Ca3Ru2O7.
Article
Chemistry, Physical
Linghan Zhu, Haonan Wang, Li Yang
Summary: In this study, we reveal a remarkable many-electron effect where doped carriers form a 2D plasmon and strongly couple with quasiparticles to renormalize moire potential and achieve ultra-flat bands. We demonstrate this effect in twisted MoS2/WS2 heterobilayer and predict that doping can effectively control the competition between correlated mechanisms, potentially leading to a quantum transition between Mott and charge-transfer insulating states.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Multidisciplinary Sciences
Javier del Valle, Nicolas M. Vargas, Rodolfo Rocco, Pavel Salev, Yoav Kalcheim, Pavel N. Lapa, Coline Adda, Min-Han Lee, Paul Y. Wang, Lorenzo Fratino, Marcelo J. Rozenberg, Ivan K. Schuller
Summary: The study utilized in-operando optical reflectivity to investigate the growth dynamics of the metallic phase, revealing that filament formation is triggered by nucleation at hotspots. By comparing three case studies, the resistivity change was identified as the crucial parameter governing this process.
Article
Materials Science, Multidisciplinary
Hengdi Zhao, Hao Zheng, Jasminka Terzic, Wenhai Song, Yifei Ni, Yu Zhang, Pedro Schlottmann, Gang Cao
Summary: Ca3Ru2O7 is a correlated and spin-orbit coupled system with extraordinary anisotropy, exhibiting conflicting phenomena with traditional precedents, such as quantum oscillations in the nonmetallic state and colossal magnetoresistivity achieved by avoiding a fully spin-polarized state. The lattice-dependent magnetotransport mechanism of Ca3Ru2O7 allows for exquisite control of the electronic state via stretching or shrinking the crystalline axes magnetically, with spin polarization playing an unconventional role in conductivity maximization. The anisotropic magnetostriction leads to exotic states at the heart of the intriguing physics in this material.
Article
Multidisciplinary Sciences
Aditya Sood, Xiaozhe Shen, Yin Shi, Suhas Kumar, Su Ji Park, Marc Zajac, Yifei Sun, Long-Qing Chen, Shriram Ramanathan, Xijie Wang, William C. Chueh, Aaron M. Lindenberg
Summary: Understanding the pathways and time scales underlying electrically driven insulator-metal transitions is vital for uncovering the fundamental limits of device operation. By using stroboscopic electron diffraction, researchers discovered an electrically triggered, isostructural state that forms transiently on microsecond time scales and established electrical excitation as a route for uncovering nonequilibrium and metastable phases in correlated materials. This metastable phase is similar to that formed under photoexcitation within picoseconds, suggesting a universal transformation pathway.
Article
Chemistry, Multidisciplinary
Federico Mazzola, Sandeep Kumar Chaluvadi, Vincent Polewczyk, Debashis Mondal, Jun Fujii, Piu Rajak, Mahabul Islam, Regina Ciancio, Luisa Barba, Michele Fabrizio, Giorgio Rossi, Pasquale Orgiani, Ivana Vobornik
Summary: This study demonstrates a genuine Mott transition without any symmetry breaking side effects in thin films of V2O3 using material synthesis and photoelectron spectroscopy. The spectral signal evolves slowly over a wide temperature range approaching the metal-insulator transition, with the Fermi wave-vector remaining unchanged and a lower critical temperature than that reported for the bulk.
Article
Physics, Multidisciplinary
G. Gatti, J. Issing, L. Rademaker, F. Margot, T. A. De Jong, S. J. van der Molen, J. Teyssier, T. K. Kim, M. D. Watson, C. Cacho, P. Dudin, J. Avila, K. Cordero Edwards, P. Paruch, N. Ubrig, I. Gutierrez-Lezama, A. F. Morpurgo, A. Tamai, F. Baumberger
Summary: Researchers used real- and momentum-space mapping techniques to study moire superlattice effects in twisted WSe2, revealing a split-off flat band from monolayer Γ states and quantifying the moire potential directly. They demonstrated that the global valence band maximum and the flat band derived from monolayer K states are close in energy, but with weaker superlattice effects. These findings constrain theoretical models and suggest the involvement of Γ-valley flat bands in the correlated physics of twisted WSe2.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Ming Xie, Haining Pan, Fengcheng Wu, Sankar Das Sarma
Summary: The effect of interelectron Coulomb interactions on the displacement field induced topological phase transition in transition metal dichalcogenide heterobilayers is studied. It is found that a nematic excitonic insulator phase can exist when the interlayer tunneling is weak or when the Coulomb interaction is not strongly screened. The nematicity arises from the frustration between the nontrivial spatial structure of the interlayer tunneling and the interlayer coherence induced by the Coulomb interaction.
PHYSICAL REVIEW LETTERS
(2023)
