Article
Multidisciplinary Sciences
Maximilian Thees, Min-Han Lee, Rosa Luca Bouwmeester, Pedro H. Rezende-Goncalves, Emma David, Alexandre Zimmers, Franck Fortuna, Emmanouil Frantzeskakis, Nicolas M. Vargas, Yoav Kalcheim, Patrick Le Fevre, Koji Horiba, Hiroshi Kumigashira, Silke Biermann, Juan Trastoy, Marcelo J. Rozenberg, Ivan K. Schuller, Andres F. Santander-Syro
Summary: This study reveals the temperature-induced MIT in V2O3, characterized by the disappearance of its itinerant conduction band and the shift to larger binding energies of a quasi-localized state. These changes were observed through the energy- and momentum-resolved electronic structure using ARPES.
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
Multidisciplinary Sciences
Xi Wang, Chengxin Xiao, Heonjoon Park, Jiayi Zhu, Chong Wang, Takashi Taniguchi, Kenji Watanabe, Jiaqiang Yan, Di Xiao, Daniel R. Gamelin, Wang Yao, Xiaodong Xu
Summary: Many-body interactions between carriers play a crucial role in correlated physics. This study demonstrates the ability to highly tune spin-spin interactions between moire-trapped carriers using optical excitation, resulting in ferromagnetic order in WS2/WSe2 moire superlattices. The observed phenomenon adds a dynamic tuning knob to the rich many-body Hamiltonian of moire quantum matter.
Article
Chemistry, Multidisciplinary
Eti Barazani, Dip Das, Chubin Huang, Abhishek Rakshit, Cecile Saguy, Pavel Salev, Javier del Valle, Maytal Caspary Toroker, Ivan K. K. Schuller, Yoav Kalcheim
Summary: The effects of strain on the metal-insulator phase transitions in V2O3 are explored. It is found that the expansion of the ab-plane is crucial for inducing negative pressure effects in the films. The findings provide insights into manipulating a Mott transition in V2O3 and expanding its potential applications in electronics.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
P. Homm, M. Menghini, J. W. Seo, S. Peters, J-P Locquet
Summary: The study demonstrates a room temperature Mott metal-insulator transition in 1.5% Cr-doped and pure V2O3 thin films by controlling phase transitions through epitaxial strain. The engineered in-plane lattice constant serves as a tunable parameter for stabilization of structure and properties, leading to unique features unseen in bulk materials. This approach offers a radical new way to create the next generation of Mott devices.
Article
Materials Science, Multidisciplinary
Manuel I. Diaz, Jong E. Han, Camille Aron
Summary: Motivated by the resistive switchings in transition-metal oxides induced by a voltage bias, this study investigates the far-from-equilibrium dynamics of an electric-field-driven strongly correlated model. It reveals that the electric field can drive both metal-to-insulator and insulator-to-metal transitions, and these transitions can be unified in a single framework once the excitations are accounted for in terms of an effective temperature.
Article
Nanoscience & Nanotechnology
Aidan J. Campbell, Mauro Brotons-Gisbert, Hyeonjun Baek, Valerio Vitale, Takashi Taniguchi, Kenji Watanabe, Johannes Lischner, Brian D. Gerardot
Summary: This study investigates the behavior of exciton-polarons in strongly correlated electronic states and reveals the rich potential of the MoSe2/WSe2 platform.
NPJ 2D MATERIALS AND APPLICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Ahyoung Kim, Soo Yeon Lim, Jung Hyun Park, Jin-Seok Chung, Hyeonsik Cheong, Changhyun Ko, Jong-Gul Yoon, Sang Mo Yang
Summary: This study investigated the temperature-dependent nanoscale conduction in a VO2 film using C-AFM, revealing conductive regions near grain boundaries and the coexistence of different monoclinic phases. Further analysis using I-V spectroscopy and deep data analysis identified the conduction mechanism as the Poole-Frenkel mechanism. This work provides deep insight into the behavior of VO2 thin films and highlights the power of I-V spectroscopy combined with deep data analysis.
Article
Materials Science, Multidisciplinary
Joel Hutchinson, Philipp W. Klein, Karyn Le Hur
Summary: This study introduces a stochastic functional approach for interacting topological insulators, including both charge and spin channels. The Mott transition of the Kane-Mele-Hubbard model is found to be described by a variational principle with one equation, and different viewpoints are presented. The stability of the transition line towards fluctuations is demonstrated, and the Mott phase is characterized by antiferromagnetism in the x-y plane, while the interacting topological phase is described through a Z(2) number related to helical edge modes. These results suggest that further insight on understanding interacting phases of matter can be gained through improving stochastic approaches.
Article
Physics, Multidisciplinary
Jiawei Zang, Jie Wang, Jennifer Cano, Antoine Georges, Andrew J. Millis
Summary: In this study, a comprehensive analysis of the triangular lattice moire??Hubbard model was conducted to investigate the physics of moire?? bilayer transition metal dichalcogenides. The results reveal the correlation between the band structure and important properties such as resistivity, magnetic order, and metal-insulator transition. The findings provide insights into the behavior of correlated states in twisted homobilayer WSe2 and heterobilayer MoTe2/WSe2 experiments.
Article
Materials Science, Multidisciplinary
Wei-Fan Hsu, Simon Mellaerts, Claudio Bellani, Pia Homm, Noriyuki Uchida, Mariela Menghini, Michel Houssa, Jin Won Seo, Jean-Pierre Locquet
Summary: Transition metal oxides exhibit rich phase diagrams due to the strong interplay of multiple degrees of freedom. The Mott material V2O3 undergoes a metal-insulator transition at both room and low temperatures, driven by electronic, structural, and magnetic ordering. Using first-principle calculations and Raman spectroscopy, the phonon dynamics of V2O3 were investigated to understand the interplay of these ordering mechanisms. The results revealed that the Raman active vibrations correspond to the structural distortions observed in the phase diagram. Additionally, Raman spectroscopy on epitaxial strained Cr-doped V2O3 thin films identified the importance of local V-V dimer elongation in driving the metal-insulator transition.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Yongchang Ma, Ang Li, Yajun Li, Li Du, Chenguang Zhang
Summary: The dielectric properties of the various insulating phases in pure V2O3 and (V0.989Cr0.011)2O3 crystals were investigated. Large dielectric constants on the scale of 10^3 were obtained, attributed to the backflow effect of normal carriers and the periodic charge configuration relevant to V-V dimers in an antiferromagnetic insulating state or the bond contraction of V-Cr-V in a paramagnetic insulating phase. It is proposed that if Cr dopants are arranged nearly uniformly, the charge density of (V0.989Cr0.011)2O3 in the paramagnetic insulating phase will exhibit a doping-induced wavelike distribution in real space, enhancing the system's polarization.
Article
Physics, Multidisciplinary
Mingjie Zhang, Xuan Zhao, Kenji Watanabe, Takashi Taniguchi, Zheng Zhu, Fengcheng Wu, Yongqing Li, Yang Xu
Summary: We observe special behaviors of electrons in the moiré superlattice formed between trilayer MoTe2 and monolayer WSe2, including the Pomeranchuk effect, Fermi liquid characteristics, and Lifshitz transition. These results suggest that this system is a unique platform to study rich correlation effects at an intermediate interaction strength.
Article
Physics, Multidisciplinary
Igor N. Karnaukhov
Summary: In this study, the topological Mott transition in a two-band model of spinless fermions on a square lattice at half filling was investigated by considering the combined effect of the on-site Coulomb repulsion and the spin-orbit Rashba coupling. The ground state phase diagram was calculated, revealing a distinct phase of matter called the topological semimetal resulting from the spin-orbit Rashba coupling. A new type of phase transition between the non-topological insulator and topological semimetal states was studied.
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
Chemistry, Physical
Stefano Dal Forno, Natsumi Komatsu, Michael Wais, Ali Mojibpour, Indrajit Wadgaonkar, Saunab Ghosh, Yohei Yomogida, Kazuhiro Yanagi, Karsten Held, Junichiro Kono, Marco Battiato
Summary: The study investigates excitonic effects in 1D semiconductors, revealing that the Sommerfeld factor is less than 1 in such systems while it is greater than 1 in 2D and 3D systems. Using a theoretical model, the absorption spectra of carbon nanotube films were fitted, uncovering the mechanism behind background absorption.
Article
Nanoscience & Nanotechnology
Judith Gabel, Matthias Pickem, Philipp Scheiderer, Lenart Dudy, Berengar Leikert, Marius Fuchs, Martin Stuebinger, Matthias Schmitt, Julia Kuespert, Giorgio Sangiovanni, Jan M. Tomczak, Karsten Held, Tien-Lin Lee, Ralph Claessen, Michael Sing
Summary: Thin films of transition metal oxides are affected by oxygen adatoms on the surface, leading to the formation of an electronically dead surface layer and altering the band filling and electron correlations. It is important to consider the presence of surface apical oxygen when predicting the behavior of ultrathin films of transition metal oxides.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Paul Worm, Liang Si, Motoharu Kitatani, Ryotaro Arita, Jan M. Tomczak, Karsten Held
Summary: Motivated by recent discoveries in nickelate compounds, this study investigates the effect of electronic correlations on their superconducting properties. For the pentalayer nickelate Nd6Ni5O12, correlations are found to push the material into the superconducting doping range, while for the bilayer nickelate Nd3Ni2O6, correlations result in a three-orbital regime. The findings suggest that substituting ions can restore the single-orbital physics with optimal doping.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Ruxin Liu, Liang Si, Wei Niu, Xu Zhang, Zhongqiang Chen, Changzheng Zhu, Wenzhuo Zhuang, Yongda Chen, Liqi Zhou, Chunchen Zhang, Peng Wang, Fengqi Song, Lin Tang, Yongbing Xu, Zhicheng Zhong, Rong Zhang, Xuefeng Wang
Summary: Through UV-light irradiation, a photocarrier-doping-induced Mott-insulator-to-metal phase transition is observed in a few atomic layers of perovskite intermediate-spin ferromagnetic SrRuO3-delta. This new metastable metallic phase can be reversibly regulated by the convenient photocharge transfer from SrTiO3 substrates to SrRuO3-delta ultrathin films.
ADVANCED MATERIALS
(2023)
Article
Computer Science, Interdisciplinary Applications
Josef Kaufmann, Karsten Held
Summary: This article presents the Python package ana_cont, which is used for the analytic continuation of fermionic and bosonic many-body Green's functions using either the Pade approximants method or the maximum entropy method. The determination of hyperparameters and the implementation are described in detail. The code is publicly available on GitHub, where documentation and learning resources are also provided.
COMPUTER PHYSICS COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Jiuxiang Zhang, Zhesheng Chen, Jonathan Caillaux, Yannick Klein, Andrea Gauzzi, Azzedine Bendounan, Amina Taleb-Ibrahimi, Luca Perfetti, Evangelos Papalazarou, Marino Marsi
Summary: Time-resolved ARPES provides a method to investigate the band structure and dynamics of excited electronic states in solids. Understanding the orbital character of bands near the Fermi level is crucial for explaining exotic phenomena in quantum materials. By conducting polarization-dependent time-and angle-resolved photoemission spectroscopy and analyzing the photoelectron yield for different crystal orientations, we determine the orbital character of bands above and below the chemical potential in the Dirac semimetal BaNiS2. Our results demonstrate the significance of controlling and understanding matrix elements' effects in time-resolved photoemission spectroscopy for the study of quantum materials.
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2023)
Article
Physics, Multidisciplinary
Nan Liu, Xiao-Chao Wang, LIang Si
Summary: By employing DFT and DMFT calculations, the structural, electronic, and magnetic characteristics of Sr2RuO4 and SrRuO3 at 50% Fe-doping level are studied, revealing their potential applications in high-performance spintronic devices.
Article
Materials Science, Multidisciplinary
Patrick Kappl, Friedrich Krien, Clemens Watzenboeck, Karsten Held
Summary: By calculating the three-particle response of the Anderson impurity model, we find that genuine three-particle vertex corrections are significant and cannot be neglected by only considering bare bubble terms or corrections based on the two-particle vertex.
Article
Materials Science, Multidisciplinary
Liang Si, Paul Worm, Dachuan Chen, Karsten Held
Summary: Despite extensive experimental and theoretical efforts, understanding the magnetic and electronic properties of superconducting nickelates remains challenging due to hidden factors in the synthesized films. One possible hidden factor is the intercalation of hydrogen during the chemical reduction process. The formation of hydrogen chains in LaNiO2 superconductors may explain the observed charge order states and make synthesizing homogeneous nickelates more difficult.
Article
Materials Science, Multidisciplinary
Ruiqi Ku, Luo Yan, Jian-Guo Si, Songyuan Zhu, Bao-Tian Wang, Yadong Wei, Kaijuan Pang, Weiqi Li, Liujiang Zhou
Summary: Based on first principles, this study investigates the Janus 2H-MoSH monolayer and reports the global minimum structure of a Janus 1T-MoSH monolayer. The 2H-MoSH monolayer can easily transform into the 1T phase with a small barrier. The Janus 1T-MoSH is a charge-density wave (CDW) material whose CDW order can be regulated through external strains. Under 3% compressive strain, the CDW in Janus 1T-MoSH is suppressed and a superconducting state with a transition temperature of 25.15 K emerges. The Janus 2H-MoSH monolayer is an intrinsic superconductor with a transition temperature of 26.81 K, which can be enhanced to 36.69 K under 1% tensile strain.
Article
Materials Science, Multidisciplinary
Simone Di Cataldo, Paul Worm, Liang Si, Karsten Held
Summary: A recent experiment suggests that superconductivity in nickelates is limited to a specific range of hydrogen concentration. The necessity of hydrogen indicates its crucial role in superconductivity. However, calculations using density-functional theory show that the electron-phonon coupling in hydrogen-intercalated nickelates is not strong enough to explain the observed superconductivity.
Article
Materials Science, Multidisciplinary
C. Watzenboeck, M. Wallerberger, L. Ruzicka, P. Worm, K. Held, A. Kauch
Summary: In this study, we investigate photoexcitations in small Hubbard clusters and find that some clusters exhibit an increase in double occupation through impact ionization after an electric field pulse. By treating the electromagnetic field classically and using exact diagonalization, we are able to identify the many-body eigenstates responsible for impact ionization and observe pronounced changes in double occupation and spin energy. Our analysis shows that the increase in spin energy is not significant for impact ionization. We also demonstrate that the characteristic peak structure of the optical conductivity in one-dimensional chains is solely due to vertex corrections.
Article
Materials Science, Multidisciplinary
Motoharu Kitatani, Ryotaro Arita, Thomas Schaefer, Karsten Held
Summary: We review recent studies on superconductivity using diagrammatic extensions of dynamical mean field theory, which consider both local correlation effects and spatial long-range fluctuations. The results reproduce and predict experimental phase diagrams of strongly correlated systems, and reveal that the dynamical screening effect of the pairing interaction vertex has significant consequences for the transition temperature.
JOURNAL OF PHYSICS-MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Paul Worm, Motoharu Kitatani, Jan M. Tomczak, Liang Si, Karsten Held
Summary: In this study, a bilayer structure of Ba2CuO3+y was revealed using density-functional theory and dynamical mean-field theory. It was found that interlayer self-doping leads to a quasi-one-dimensional band with strong nesting and antiferromagnetic fluctuations, possibly responsible for the superconductivity in Ba2CuO3+y.
