Article
Materials Science, Multidisciplinary
J. F. Nossa, M. F. Islam, Mark R. Pederson, C. M. Canali
Summary: Frustrated triangular molecular magnets are important for their spin-electric coupling, which allows for efficient and fast manipulation of spin states and makes them attractive for quantum information processing. This study conducts first-principles calculations on the spin-electric coupling in a {V3} triangular magnetic molecule and investigates the spin-induced charge redistribution that contributes to the coupling. The method used is then generalized to calculate the coupling strength in {V15} molecular magnets.
Article
Physics, Multidisciplinary
J. Khatua, M. Gomilsek, J. C. Orain, A. M. Strydom, Z. Jaglicic, C. Colin, S. Petit, A. Ozarowski, L. Mangin-Thro, K. Sethupathi, M. S. Ramachandra Rao, A. Zorko, P. Khuntia
Summary: Researchers experimentally investigate a frustrated magnet, Li4CuTeO6, and provide evidence suggesting the presence of a random-singlet ground state in this material.
COMMUNICATIONS PHYSICS
(2022)
Article
Physics, Multidisciplinary
Qing Yu-Lin, Peng Xiao-Li, Hu Ai-Yuan
Summary: This paper investigates the phase transition of the spin-1 frustrated model on a square-lattice bilayer using the double-time Green's function method. The effects of the interlayer coupling parameter J(c) and single-ion anisotropy D on the phase transformation between the Neel state (AF1) and collinear state (AF2) are explored. The results show that a first-order phase transformation between these two states can occur below the critical point if both J(c) and D are not equal to zero simultaneously.
ACTA PHYSICA SINICA
(2022)
Article
Materials Science, Multidisciplinary
S. Seyedi, F. Heydarinasab, J. Abouie
Summary: This study investigates the ground-state phase diagram of frustrated mixed-spin chains, revealing various magnetic and nonmagnetic phases. One magnetic phase with dispersionless magnon excitations is found, a unique feature arising from the inhomogeneity of the chains.
Article
Materials Science, Multidisciplinary
Alexander Mook, Rhea Hoyer, Jelena Klinovaja, Daniel Loss
Summary: We study quantum condensed matter systems where particle number is not conserved, leading to topological anticrossings in the spectrum due to hybridization of states from different particle-number sectors. This phenomenon is observed in fully saturated spin-anisotropic quantum magnets, where single magnons hybridize with magnon bound pairs. The resulting chiral edge excitations are composite particles with mixed spin-multipolar character, showing genuine quantum mechanical effects that vanish in the classical limit. These findings have implications for intrinsic anomalous Hall-type transport, suggesting that fully polarized quantum magnets can serve as a promising platform for studying topological effects caused by hybridizations between particle-number sectors.
Article
Materials Science, Multidisciplinary
A. Miyata, T. Hikihara, S. Furukawa, R. K. Kremer, S. Zherlitsyn, J. Wosnitza
Summary: The magnetoelastic properties of the quasi-one-dimensional spin-1/2 frustrated magnet LiCuVO4 were investigated under high magnetic fields. The magnetostriction data resembles the magnetization results, and can be explained by an exchange-striction mechanism. Small deviations found in the data may indicate nontrivial changes in local correlations associated with field-induced phase transitions.
Article
Materials Science, Multidisciplinary
Dario Fiore Mosca, Leonid Pourovskii, Beom Hyun Kim, Peitao Liu, Samuele Sanna, Federico Boscherini, Sergii Khmelevskyi, Cesare Franchini
Summary: In this work, the complex entanglement between spin interactions, electron correlation, and Janh-Teller structural instabilities in the 5d(1) J(eff) = 3/2 spin-orbit coupled double perovskite Ba2NaOsO6 is studied using first principles approaches. The origin of the observed quadrupolar canted antifferomagnetic is elucidated by combining noncollinear magnetic calculations with multipolar pseudospin Hamiltonian analysis and many-body techniques. It is found that the transition between different magnetic orders can be controlled by the strength of electronic correlation and the degree of Jahn-Teller distortions.
Article
Multidisciplinary Sciences
K. Komedera, J. Gatlik, A. Blachowski, J. Zukrowski, D. Rybicki, A. Delekta, M. Babij, Z. Bukowski
Summary: Investigation of EuFe2-xNixAs2 compounds with 3d and/or 4f magnetic order was done using Fe-57 and Eu-151 Mossbauer spectroscopy. The study found that Ni-substitution suppresses the spin-density wave order of Fe moments, while Eu localized moments still order with a spin reorientation as Ni concentration increases. The transition from antiferromagnetic to ferromagnetic 4f spins coincides with the disappearance of 3d spins order, showing strong coupling between Eu2+ ions and conduction electrons.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Multidisciplinary
Hassan Al-Hamdo, Tobias Wagner, Yaryna Lytvynenko, Gutenberg Kendzo, Sonka Reimers, Moritz Ruhwedel, Misbah Yaqoob, Vitaliy I. Vasyuchka, Philipp Pirro, Jairo Sinova, Mathias Klaeui, Martin Jourdan, Olena Gomonay, Mathias Weiler
Summary: We investigated the magnetization dynamics of Mn2Au/Py thin film bilayers and found two resonant modes that are attributed to the coupling between Py and Mn2Au.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
David Jacob, Ricardo Ortiz, Joaquin Fernandez-Rossier
Summary: The study focuses on spin excitations and the Kondo effect in open-shell nanographenes, considering the impact of hybridization with a conducting substrate. The results show that the coupling to the substrate leads to significant renormalization of spin flip excitation energies, broadening of spectral features, and the emergence of zero bias Kondo peaks for the S = 1 ground states. The calculated substrate-induced shift of spin excitation energies is found to be larger than their broadening, emphasizing the importance of considering this effect when comparing experimental results and theory.
Article
Physics, Applied
Nityananda Acharyya, Vaishnavi Sajeev, Shreeya Rane, Subhajit Karmakar, Dibakar Roy Chowdhury
Summary: Metal-based magnetic multilayers are crucial for giant-magnetoresistance (GMR) in magnetic memory devices and spintronic applications. This study investigates the magnetoresistive effect in Al/Ni/Al/Ni/Al spin valve structures using contactless terahertz (THz) spectroscopy. The results demonstrate magnetic field-dependent conductivity enhancement in the multilayers, showing potential for low power THz magnetism and dynamically controllable THz devices.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
M. Mohylna, F. A. Gomez Albarracin, M. Zukovic, H. D. Rosales
Summary: This study reveals the emergence of a spontaneous antiferromagnetic skyrmion/antiskyrmion lattice in the classical Heisenberg antiferromagnet on the triangular-lattice under magnetic fields. These findings are significant for the research on antiferromagnetic skyrmions in centrosymmetric materials or lattices with relatively weak Dzyaloshinskii-Moriya interaction.
Article
Materials Science, Multidisciplinary
Santanu De, Amit Chauhan, B. R. K. Nanda, A. Banerjee
Summary: The Ising magnetism in the CCO system is attributed to the large contribution of orbital moment to magnetization and strong magnetocrystalline anisotropy. The study reveals the role of spin-orbit coupling and crystal-field effects in this Ising character of magnetism through the temperature and field dependence of magnetization in the presence of hydrostatic pressures. The interplay of trigonal crystal-field and spin-orbit coupling effects is further demonstrated through a quantitative analysis of field-dependent magnetization.
Article
Chemistry, Physical
Li Wang, Jie Qin, Youyuan Ran, Lan Chen
Summary: This study presents a novel uranium-fluorine compound with a three-dimensional five-connected geometrical spin-frustrated lattice, which exhibits strong antiferromagnetic interactions without magnetic ordering, suggesting its potential as a candidate for quantum spin liquid behavior.
Article
Chemistry, Inorganic & Nuclear
Joscha Nehrkorn, Samuel M. Greer, Brian J. Malbrecht, Kevin J. Anderton, Azar Aliabadi, J. Krzystek, Alexander Schnegg, Karsten Holldack, Carmen Herrmann, Theodore A. Betley, Stefan Stoll, Stephen Hill
Summary: This study presents a comprehensive spectroscopic investigation of the unique single-molecule magnet Fe-6, revealing its isolated nature of the spin ground state and providing insights into the factors governing the quantum tunneling of its magnetization. The work suggests strategies for improving the performance of polynuclear SMMs featuring direct metal-metal bonds and strong ferromagnetic spin-spin interactions.
INORGANIC CHEMISTRY
(2021)
Article
Materials Science, Multidisciplinary
Rajyavardhan Ray, Banasree Sadhukhan, Manuel Richter, Jorge I. Facio, Jeroen van den Brink
Summary: Even if Weyl semimetals are characterized by quasiparticles with well-defined chirality, the experimental exploitation of this feature is severely limited by pairs of Weyl lattice fermions with opposite chirality, causing the net chirality to vanish. However, this issue can be overcome when both time-reversal and inversion symmetry are broken. By investigating chirality in the carbide family RMC2, we found several members to be Weyl semimetals and demonstrated in NdRhC2, a noncentrosymmetric ferromagnet, that an odd number of Weyl nodes can be stabilized at its Fermi surface by tilting its magnetization. The resulting chiral configuration leads to topological phase transitions and interesting chiral electromagnetic responses, and the tilt direction determines the sign and strength of the net chirality.
NPJ QUANTUM MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Yaqian Guo, Hui Liu, Oleg Janson, Ion Cosma Fulga, Jeroen van den Brink, Jorge I. Facio
Summary: It has been discovered that collinear antiferromagnets, depending on their symmetries, can break the spin degeneracy in momentum space without spin-orbit coupling. These systems, known as altermagnets, are characterized by a spin-momentum texture determined by crystal and magnetic structure. This study focuses on q = 0 antiferromagnetic compounds in the MAGNDATA database and introduces numerical measures for average momentum-space spin splitting, analyzing over sixty compounds including CoF2, FeSO4F, LiFe2F6, RuO2, CrNb4S8, and CrSb.
MATERIALS TODAY PHYSICS
(2023)
Article
Multidisciplinary Sciences
Hiroki Ueda, Mirian Garcia-Fernandez, Stefano Agrestini, Carl P. Romao, Jeroen van den Brink, Nicola A. Spaldin, Ke-Jin Zhou, Urs Staub
Summary: The concept of chirality plays a crucial role in various natural phenomena. Recent studies in condensed matter physics have revealed the existence of chiral fermions and their connection to emergent phenomena and topology. However, experimental verification of chiral phonons in macroscopic systems remains challenging. In this study, we provide experimental evidence of chiral phonons using resonant inelastic X-ray scattering with circularly polarized X-rays. By studying the chiral material quartz, we demonstrate that circularly polarized X-rays couple to chiral phonons at specific positions in reciprocal space, allowing for the determination of the chiral dispersion of lattice modes. This experimental proof of chiral phonons introduces a new degree of freedom in condensed matter physics, with both fundamental importance and potential for exploring novel emergent phenomena based on chiral bosons.
Article
Materials Science, Multidisciplinary
Dennis Wawrzik, Jorge I. Facio, Jeroen van den Brink
Summary: In recent years, the concept of electronic Berry curvature (BC) has been recognized as crucial for understanding and predicting physical properties of crystalline materials. While non-magnetic materials with inversion symmetry have a strictly zero BC in their bulk, we demonstrate that a finite BC can emerge at their surfaces and interfaces, resulting in Hall-type transport responses. Through first principles calculations, we observe the presence of a surface Berry curvature dipole and associated quantum nonlinear Hall effects at various symmetries of bismuth, mercury-telluride (HgTe), and rhodium surfaces. This discovery opens up a wide range of materials to explore and harness the physical effects arising from electronic Berry curvature exclusively at their boundaries.
MATERIALS TODAY PHYSICS
(2023)
Article
Physics, Applied
Rakshanda Dhawan, Vikrant Chaudhary, Chandan Kumar Vishwakarma, Mohd Zeeshan, Tashi Nautiyal, Jeroen van den Brink, Hem C. Kandpal
Summary: Anomalous carrier transport in magnetic Heusler compounds has attracted significant attention due to their unique band structure and broken time-reversal symmetry. In this study, we investigate the properties of CoFeSn and propose a cubic polymorph based on structural stability, lattice dynamics, and magnetic analysis. Utilizing density-functional-theory calculations, we predict that cubic CoFeSn exhibits robust half-metallic ferromagnetic behavior with a high Curie temperature and significant spin Hall conductivity. We also find that adjusting the Fermi level can enhance the anomalous Hall conductivity or spin Hall conductivity. Our findings provide important insights for the realization of quantum anomalous and spin Hall effects in half-Heusler compounds.
APPLIED PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Wuyang Ren, Wenhua Xue, Shuping Guo, Ran He, Liangzi Deng, Shaowei Song, Andrei Sotnikov, Kornelius Nielsch, Jeroen van den Brink, Guanhui Gao, Shuo Chen, Yimo Han, Jiang Wu, Ching-Wu Chu, Zhiming Wang, Yumei Wang, Zhifeng Ren
Summary: Studies have shown that vacancy-mediated anomalous transport properties are flourishing in various fields due to their fascinating effects on photoelectric, ferroelectric, and spin-electric behaviors in solid materials. In this study, the authors reveal the multifunctionality of vacancy in tailoring the transport properties of a defective half-Heusler ZrNiBi material, providing insights into the phononic and electronic transport processes. These findings not only demonstrate the potential of this thermoelectric material but also promote further exploration of vacancy-mediated transport properties.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Carmine Ortix, Jeroen van den Brink
Summary: Magnetoelectric crystals have the ability to convert electric fields into magnetic polarizations and magnetic fields into ferroelectric polarizations. In this study, a new method is proposed to achieve linear magnetoelectric coupling in ferromagnetic insulators using nanoscale curved geometries and intrinsic Dzyaloshinskii-Moriya interaction (DMI). The reorganization of the magnetic texture induced by the combination of curved geometries and DMI breaks inversion symmetry and creates macroscopic magnetoelectric multipoles. This study demonstrates the activation of a magnetoelectric monopole in two-dimensional magnets through controlled ripples and the direct linear magnetoelectric coupling in zigzag-shaped ferromagnetic wires.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Viktor Koenye, Lotte Mertens, Corentin Morice, Dmitry Chernyavsky, Ali G. Moghaddam, Jasper van Wezel, Jeroen van den Brink
Summary: We demonstrate that tilted Weyl semimetals with spatially varying tilt can be used to study anisotropic optics and curved spacetime. By examining specific tilting configurations, we numerically analyze the time evolution of electronic wave packets and current densities. Our results show that electron trajectories in such systems can be determined using Fermat's principle with an inhomogeneous, anisotropic effective refractive index. Additionally, we show that these systems can simulate gravitational lensing around a synthetic black hole, revealing gravitational features.
Article
Physics, Multidisciplinary
Ayushi Singhania, Jeroen van den Brink, Satoshi Nishimoto
Summary: This study investigates the interplay of disorder and Heisenberg interactions in the Kitaev model on a honeycomb lattice. The effects of disorder on the transition between Kitaev spin liquid and magnetic ordered states as well as the stability of magnetic ordering are examined. The results show that disorder reduces the range of spin-liquid phases and changes the transitions to magnetic ordered phases to a more crossoverlike behavior. In addition, long-range orderings in the clean system are replaced by domains with different ordering directions.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Shruti Agarwal, Shreekant Gawande, Satoshi Nishimoto, Jeroen Van den Brink, Sanjeev Kumar
Summary: Using a combination of mean-field Bogoliubov-de Gennes approach and density matrix renormalization group method, we discovered first-order topological transitions between topological superconducting and trivial insulating phases in a sawtooth lattice of intersite attractive fermions. The topological properties of different phases were characterized in terms of winding numbers, Majorana edge modes, and entanglement spectra. By studying the effect of disorder on first-order topological phase transitions, we established disorder-induced topological phase coexistence as a mechanism for generating a finite density of Majorana particles.
Article
Physics, Multidisciplinary
Viktor Koenye, Corentin Morice, Dmitry Chernyavsky, Ali G. Moghaddam, Jeroen van den Brink, Jasper van Wezel
Summary: In this study, we simulate the dynamics of massless Dirac fermions in curved space-times with one, two, and three spatial dimensions by constructing tight-binding Hamiltonians with spatially varying hoppings. These models represent tilted Weyl semimetals where the tilting varies with position, similar to the light cones near the horizon of a black hole. We demonstrate the gravitational analogies in these models by numerically evaluating the propagation of wave packets on the lattice and comparing them to the geodesics of the corresponding curved space-time. We also show that the motion of electrons in these spatially varying systems can be understood through the conservation of energy and the quasiconservation of quasimomentum. Furthermore, we reveal that horizons in the lattice models can be constructed with finite energies using specially designed tilting profiles.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
Gabriele Naselli, Ali G. Moghaddam, Solange Di Napoli, Veronica Vildosola, Ion Cosma Fulga, Jeroen van den Brink, Jorge I. Facio
Summary: We analyze the electronic structure of topological surface states in the family of magnetic topological insulators. We show that, at the magnetic ordering temperature, the symmetry of the Dirac cone warping changes from hexagonal to trigonal, leading to energy splitting between surface states. This energy splitting can be used as a simple protocol to detect magnetic ordering via the surface electronic structure.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Shiang Fang, Linda Ye, Madhav Prasad Ghimire, Mingu Kang, Junwei Liu, Minyong Han, Liang Fu, Manuel Richter, Jeroen van den Brink, Efthimios Kaxiras, Riccardo Comin, Joseph G. Checkelsky
Summary: In this study, we investigated the electronic structure of the ferromagnetic kagome metal Fe3Sn2 without spin-orbit coupling. We found two energetically split helical nodal lines near K and K' in the Brillouin zone, resulting from the trigonal stacking of the kagome layers. The hopping across A-A stacking introduced energy splitting, while that across A-B stacking controlled the momentum space amplitude of the helical nodal lines. Our findings have important implications for the design of topological materials.
Article
Physics, Multidisciplinary
Viktor Koenye, Adrien Bouhon, Ion Cosma Fulga, Robert-Jan Slager, Jeroen van den Brink, Jorge I. Facio
Summary: Weyl cones in topological semimetals are typically robust, but their topological charge can actually change sign through the merging of three Weyl nodes. The presence of rotation and time-reversal symmetries constrains the relative positions of Weyl cones in momentum space, facilitating the chirality flipping process. Our work predicts the occurrence of chirality flip in MoTe2, highlighting the potential to observe such processes in different topological materials.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Physics, Multidisciplinary
Corentin Morice, Ali G. Moghaddam, Dmitry Chernyavsky, Jasper van Wezel, Jeroen van den Brink
Summary: The study introduces a lattice model that can mimic phenomena similar to black hole event horizons and realize (1+1)D spacetime under certain conditions. When the position-dependent hopping integrals are influenced by specific factors, wave packets exhibit different behaviors on the lattice.
PHYSICAL REVIEW RESEARCH
(2021)
