Article
Physics, Multidisciplinary
Evgeny A. Stepanov, Yusuke Nomura, Alexander I. Lichtenstein, Silke Biermann
Summary: This study investigates the spatial symmetry and orbital structure of magnetic fluctuations in perovskite materials using a consistent multiorbital diagrammatic extension of dynamical mean-field theory. The findings reveal that the local Hund's coupling plays a significant role in determining the form of spatial spin fluctuations, with small coupling leading to anisotropic fluctuations and large coupling enhancing collective spin excitations. Additionally, the study demonstrates that orbital isotropy can be induced under certain conditions, impacting the magnetic instability of the system.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Wenxuan Zhu, Cheng Song, Yongjian Zhou, Qian Wang, Hua Bai, Feng Pan
Summary: In this work, it is found through first-principle calculations that the interlayer magnetic coupling in 2D magnetic bilayers is determined by the stacking order of interlayer nonmagnetic atoms. Adjusting the structure of interlayer nonmagnetic atoms can tune the interlayer coupling. The perspective proposed in this study is applicable in understanding interlayer magnetic coupling in other 2D materials as well.
Article
Chemistry, Multidisciplinary
Yu Wang, Zhigang Song, Jiawei Wan, Sophia Betzler, Yujun Xie, Colin Ophus, Karen C. Bustillo, Peter Ercius, Lin-Wang Wang, Haimei Zheng
Summary: This study presents a new method for synthesizing moire superlattices with strong chemical bonding, using lead sulfide as an example. Water-soluble ligands are used as a removable template to obtain ultrathin PbS nanosheets, which are then assembled into direct-contact bilayers with various twist angles. Atomic-resolution imaging reveals periodic structural reconstruction at the superlattice interface due to the strong metavalent coupling. The twist-angle-dependent electronic structure, particularly the emergence of separated flat bands, is demonstrated through electron energy loss spectroscopy and theoretical calculations. The localized states of flat bands resemble well-arranged quantum dots, suggesting potential applications in devices.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
S. Spachmann, S. Selter, B. Buchmer, S. Aswartham, R. Klingeler
Summary: Single crystals of Cr2Ge2Te6 were studied by high-resolution capacitance dilatometry to investigate thermal expansion and magnetostriction. The results revealed the presence of different phases (PM, LTF, FM) and a triple point in the magnetic phase diagram. Simulations using the Stoner-Wohlfarth model demonstrated the rotation of spins in the LTF phase from the c direction to the ab plane. The data highlighted the importance of critical fluctuations and magnetoelastic coupling in Cr2Ge2Te6.
Article
Chemistry, Physical
Hou-Yi Lyu, Zhen Zhang, Jing-Yang You, Qing-Bo Yan, Gang Su
Summary: This study achieved 2D multiferroics using intercalation technology, which exhibited excellent ferroelectric and ferromagnetic properties. It paves a practical path for the application of 2D multiferroics in spintronics.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Multidisciplinary Sciences
Martin Claassen, Lede Xian, Dante M. Kennes, Angel Rubio
Summary: The study predicts that twisted bilayers of ZrS2 with the group-IV metal Zr can form an emergent moire Kagome lattice with strong spin-orbit coupling, leading to novel topological quantum phases dominated by strong spin-orbit interactions. At small twist angles, ZrS2 heterostructures give rise to an emergent and twist-controlled moire Kagome lattice, combining geometric frustration and strong spin-orbit coupling to realize a moire quantum spin Hall insulator with highly controllable and nearly-dispersionless bands.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Wonmi Ahn, B. S. Simpkins
Summary: This study explores the Raman scattering response of a PMMA carbonyl band under vibrational strong coupling in a Fabry-Perot cavity, revealing features such as softening and a small dip near the fundamental vibrational frequency. These effects are attributed to upper and lower polaritons dispersing over the collection angle, as confirmed by control measurements and modeling.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Physics, Multidisciplinary
Sheng Liu, Andres Granados del Aguila, Dhiman Bhowmick, Chee Kwan Gan, T. Thu Ha Do, M. A. Prosnikov, David Sedmidubsky, Zdenek Sofer, Peter C. M. Christianen, Pinaki Sengupta, Qihua Xiong
Summary: In FePS3, strong coupling between magnons and phonons was directly observed using magneto-Raman spectroscopy at magnetic fields up to 30 Tesla. A hybridized magnon-phonon quasiparticle formed due to field-driven resonance with a nearby phonon mode. The polarized Raman results demonstrated the transfer of spin angular momentum from magnons to phonons, generating phonon spin through strong coupling.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Amit Pawbake, Thomas Pelini, Nathan P. Wilson, Kseniia Mosina, Zdenek Sofer, Rolf Heid, Clement Faugeras
Summary: In this study, magnetic ordering in the layered magnetic material CrSBr was directly observed in the temperature dependence of the Raman scattering response. The magnetic ordering was characterized through variations in scattered intensities, the activation of new phonon lines, and second-order Raman scattering processes. Furthermore, distinct Raman scattering signatures were identified for the different magnetic phases encountered in CrSBr.
Article
Chemistry, Multidisciplinary
Aparna Parappurath, Bhaskar Ghawri, Saisab Bhowmik, Arup Singha, K. Watanabe, T. Taniguchi, Arindam Ghosh
Summary: The ability to tune the twist angle between different layers of 2D materials has led to the creation of electronic flat bands artificially. In this study, the photoresponse of a few-layer WSe2/tBLG heterostructure was measured, and it was found that the photoresponse is sensitive to the band structure of tBLG. When the Fermi energy is within the low-energy moiré bands, the photoresponse is strongly suppressed, but it can be recovered when the Fermi energy exceeds the moiré band edge due to the photogating effect.
Article
Materials Science, Multidisciplinary
Klaus Zollner, Martin Gmitra, Jaroslav Fabian
Summary: In this study, we investigate the proximity spin-orbit and exchange couplings in ABA and ABC trilayer graphene encapsulated within monolayers of semiconducting transition-metal dichalcogenides and the ferromagnetic semiconductor Cr2Ge2Te6 using first-principles calculations. We demonstrate the tunability of the proximity effects by a transverse electric field. The study also includes the analysis of mixed spin-orbit/exchange coupling encapsulation and provides a qualitative understanding of the behavior and realistic model parameters for transport and correlation physics in trilayer graphene.
Article
Materials Science, Multidisciplinary
Shouzheng Liu, Yishuai Xu, Erica C. Kotta, Lin Miao, Sheng Ran, Johnpierre Paglione, Nicholas P. Butch, Jonathan D. Denlinger, Yi-De Chuang, L. Andrew Wray
Summary: The recent discovery of spin-triplet superconductivity in UTe2 has raised interest in understanding the mechanism of Cooper pairing. By using resonant inelastic x-ray scattering and x-ray absorption spectroscopy, researchers found that the experimental data support the models based on 5f(2)6d(1)-like valence electron configuration, providing insights for interpreting the electronic structure and superconducting pairing mechanism.
Article
Materials Science, Multidisciplinary
Kyung-Su Kim
Summary: We have proven that the motion of a single hole in the U = oo Hubbard model on a triangular cactus lattice leads to the formation of a nearest-neighbor resonating-valence-bond ground state. This result can also be applied to t-J models with antiferromagnetic interactions J0 on the same lattice structure. It serves as a weak converse of Nagaoka's theorem of ferromagnetism on a bipartite lattice.
Article
Physics, Multidisciplinary
Xiaoyu Wang, Morten H. Christensen, Erez Berg, Rafael M. Fernandes
Summary: This study investigates a class of two-dimensional two-band microscopic models with dominant inter-band repulsive interactions, proposing constrained schemes to overcome the fermionic sign-problem for efficient Quantum Monte Carlo simulations. The behavior of the models in the strong-coupling regime is studied, revealing a variety of ground states and quantum critical points accessible by varying the band structure parameters. The comparison with the single-band Hubbard model shows differences in strong-coupling behavior.
Article
Chemistry, Physical
Zhicui Wang, Huan Lou, Fanjunjie Han, Xu Yan, Yong Liu, Guochun Yang
Summary: A new FeCN2 monolayer with a unique zigzag Fe chain has been identified through first-principles swarm structural search calculations. It is an antiferromagnetic semiconductor with a direct band gap of 2.04 eV, a Neel temperature (T-N) of 176 K, and a large in-plane magnetic anisotropy energy (MAE) of 0.50 meV per Fe atom. The material exhibits intrinsic antiferromagnetism and can maintain its properties under external biaxial strains, making it a promising nanoscale spintronic material.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Abhijit Sau, Kalaivanan Nagarajan, Bianca Patrahau, Lucas Lethuillier-Karl, Robrecht M. A. Vergauwe, Anoop Thomas, Joseph Moran, Cyriaque Genet, Thomas W. Ebbesen
Summary: Vibrational strong coupling (VSC) has been shown to influence the rate and chemoselectivity of chemical reactions, with observations suggesting that symmetry considerations can be used to control chemical selectivity under VSC. In the case of pericyclic reactions, VSC affects the stereoselectivity of reactions, with changes in rate and thermodynamics depending on the coupled vibrational mode. These results confirm the key role of symmetry in chemistry under VSC.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Multidisciplinary Sciences
Kuidong Wang, Marcus Seidel, Kalaivanan Nagarajan, Thibault Chervy, Cyriaque Genet, Thomas Ebbesen
Summary: By strongly coupling the exciton of cyanine dye J-aggregates to an optical mode of a Fabry-Perot (FP) cavity, a significant enhancement of the complex nonlinear refractive index and ultrafast response can be achieved. This work paves the way for exploring strong coupling effects on various third-order nonlinear optical phenomena and for technological applications.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Kripa Joseph, Soh Kushida, Emanuel Smarsly, Dris Ihiawakrim, Anoop Thomas, Gian Lorenzo Paravicini-Bagliani, Kalaivanan Nagarajan, Robrecht Vergauwe, Eloise Devaux, Ovidiu Ersen, Uwe H. F. Bunz, Thomas W. Ebbesen
Summary: The research found that vibrational strong coupling can significantly change the molecular supermolecular morphology of self-assembly, affect self-assembly dynamics, and depend on solvent vibration. These findings provide a new tool for controlling supramolecular assemblies, with broad implications for molecular and material science.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Optics
Anne-Lise Viotti, Skirmantas Alisauskas, Henrik Tuennermann, Esmerando Escoto, Marcus Seidel, Katharina Dudde, B. Manschwetus, Ingmar Hartl, Christoph M. Heyl
Summary: Nonlinear pulse post-compression is an efficient method for producing ultrashort, high-quality laser pulses, but the temporal pulse quality is limited by amplitude and phase modulations. The study characterizes individual post-compressed pulses with high dynamic range, demonstrating nearly constant energy content in the main peak over the burst plateau. This makes multi-pass post-compressed lasers attractive for pump-probe spectroscopy and secondary frequency conversion stages.
Article
Nanoscience & Nanotechnology
Kuidong Wang, Minghao Li, Hui-Hsin Hsiao, Fengling Zhang, Marcus Seidel, Ai-Yin Liu, Jie Chen, Eloise Devaux, Cyriaque Genet, Thomas Ebbesen
Summary: The study demonstrates a large, ultrafast anisotropic modulation of light using the anisotropic nonlinear response of indium tin oxide and plasmonic nanoantennas. A polarization elliptic rotation and phase delay between the oscillations of linear polarization axes are achieved, showing promise for implementing all-optical high-speed polarization modulators and retarders.
Article
Chemistry, Physical
Kulangara Sandeep, Kripa Joseph, Jerome Gautier, Kalaivanan Nagarajan, Meleppatt Sujith, K. George Thomas, Thomas W. Ebbesen
Summary: The chemical and physical properties of molecules and materials can be significantly modified under vibrational strong coupling. In this study, the aggregation of two structural isomers of phenyleneethynylene under cooperative coupling was investigated. The results showed that coupling the aromatic C=C stretching band can lead to the formation of different structures and modified spectra, highlighting the importance of vibrational strong coupling in supramolecular chemistry.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Review
Chemistry, Multidisciplinary
Kalaivanan Nagarajan, Anoop Thomas, Thomas W. Ebbesen
Summary: Manipulating chemistry and material properties using hybrid light-matter states has attracted considerable interest in the past decade. The strong coupling phenomenon occurs in the dark and does not require real photons to induce. Vibrational strong coupling offers exciting possibilities for molecular and material science.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Optics
Marcus Seidel, Federico Pressacco, Oender Akcaalan, Thomas Binhammer, John Darvill, Nagitha Ekanayake, Maik Frede, Uwe Grosse-Wortmann, Michael Heber, Christoph M. Heyl, Dmytro Kutnyakhov, Chen Li, Christian Mohr, Jost Mueller, Oliver Puncken, Harald Redlin, Nora Schirmel, Sebastian Schulz, Angad Swiderski, Hamed Tavakol, Henrik Tuennermann, Caterina Vidoli, Lukas Wenthaus, Nils Wind, Lutz Winkelmann, Bastian Manschwetus, Ingmar Hartl
Summary: The study reports a novel FEL facility laser that combines high average power output and pulse compression for studying ultrafast processes. Compared to other lasers, this new system has improved noise figures, compactness, simplicity, and power efficiency. It provides high-energy, short-duration pulses that can be adjusted through computer control.
LASER & PHOTONICS REVIEWS
(2022)
Article
Chemistry, Multidisciplinary
Kuidong Wang, Ai-Yin Liu, Hui-Hsin Hsiao, Cyriaque Genet, Thomas Ebbesen
Summary: This study investigates a strong coupling between Mie resonant modes of high-index dielectric nanocavities and an epsilon-near-zero mode of an ultrathin indium tin oxide film. The anticrossing splitting of 220 meV is observed, and static nonlinear optical measurements reveal a large enhancement in the intensity-independent effective optical nonlinear coefficients at the coupled resonance. A transient response of about 300 fs is also observed. These ultrafast and large optical nonlinear coefficients offer a new route for strong coupling-assisted high-speed photonics.
Article
Optics
Anne-Lise Viotti, Chen Li, Gunnar Arisholm, Lutz Winkelmann, Ingmar Hartl, Christoph M. Heyl, Marcus Seidel
Summary: To meet the energy requirements of photon-hungry applications, researchers have developed a method to compress laser pulses, transforming a 0.1 GW peak power, picosecond laser into a 2.9 GW peak power, 8.2 fs ultra-short laser pulse. This compression method achieves a 120-fold pulse duration reduction, opening up possibilities for compact, efficient, and high repetition rate attosecond laser sources.
Article
Instruments & Instrumentation
A. -l. Viotti, S. Alisauskas, M. Seidel, A. Tajalli, B. Manschwetus, H. Cankaya, K. Jurkus, V. Sinkus, I. Hartl
Summary: With the FLASH2020+ upgrade, the pump-probe laser capabilities of FLASH in Hamburg will be enhanced, providing greater wavelength tunability, shorter pulse durations, and reduced arrival time jitter. A new concept for the pump-probe laser based on picosecond pulse compression is proposed, along with flexible reduction of pulse duration through spectral broadening. The system demonstrates tunable spectral coverage from 1.3 to 16 μm with sub-150 fs pulses, enabling a wide range of scientific experiments.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
