kth.sePublications
Change search
Link to record
Permanent link

Direct link
Publications (10 of 136) Show all publications
Xu, Q., Shen, Z., Pereiro, M., Sjöqvist, E., Herman, P., Eriksson, O. & Delin, A. (2023). Genetic-tunneling driven energy optimizer for spin systems. Communications Physics, 6(1), Article ID 239.
Open this publication in new window or tab >>Genetic-tunneling driven energy optimizer for spin systems
Show others...
2023 (English)In: Communications Physics, E-ISSN 2399-3650, Vol. 6, no 1, article id 239Article in journal (Refereed) Published
Abstract [en]

Finding the ground state of complex many-body systems, such as magnetic materials containing topological textures, like skyrmions, is a fundamental and long-standing problem. We present here a genetic-tunneling-driven variance-controlled optimization method, that efficiently identifies the ground state of two-dimensional skyrmionic systems. The approach combines a local energy-minimizer backend and a metaheuristic global search frontend. The method is shown to perform significantly better than simulated annealing. Specifically, we demonstrate that for the Pd/Fe/Ir(111) system, our method correctly and efficiently identifies the experimentally observed spin spiral geometry, skyrmion lattice and ferromagnetic ground states as a function of the external magnetic field. To our knowledge, no other optimization method has until now succeeded in doing this. We envision that our findings will pave the way for evolutionary computing in mapping out phase diagrams for spin systems in general.

Place, publisher, year, edition, pages
Springer Nature, 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-336301 (URN)10.1038/s42005-023-01360-4 (DOI)2-s2.0-85169699856 (Scopus ID)
Note

QC 20230913

Available from: 2023-09-13 Created: 2023-09-13 Last updated: 2023-09-13Bibliographically approved
Lu, Z., Miranda, I. P., Streib, S., Pereiro, M., Sjöqvist, E., Eriksson, O., . . . Delin, A. (2023). Influence of nonlocal damping on magnon properties of ferromagnets. Physical Review B, 108(1), Article ID 014433.
Open this publication in new window or tab >>Influence of nonlocal damping on magnon properties of ferromagnets
Show others...
2023 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 108, no 1, article id 014433Article in journal (Refereed) Published
Abstract [en]

We study the influence of nonlocal damping on the magnon properties of Fe, Co, Ni, and Fe1-xCox (x=30%,50%) alloys. The Gilbert damping parameter is typically considered as a local scalar both in experiment and in theoretical modeling. However, recent works have revealed that Gilbert damping is a nonlocal quantity that allows for energy dissipation between atomic sites. With the Gilbert damping parameters calculated from a state-of-the-art real-space electronic structure method, magnon lifetimes are evaluated from spin dynamics and linear response, where a good agreement is found between these two methods. It is found that nonlocal damping affects the magnon lifetimes in different ways depending on the system. Specifically, we find that in Fe, Co, and Ni, the nonlocal damping decreases the magnon lifetimes, while in Fe70Co30 and Fe50Co50 an opposite, nonlocal damping effect is observed, and our data show that it is much stronger in the former.

Place, publisher, year, edition, pages
American Physical Society (APS), 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-335299 (URN)10.1103/PhysRevB.108.014433 (DOI)001122919500002 ()2-s2.0-85166950613 (Scopus ID)
Note

QC 20230905

Available from: 2023-09-05 Created: 2023-09-05 Last updated: 2024-01-16Bibliographically approved
Hasan, M. N., Bharati, R., Hellsvik, J., Delin, A., Pal, S. K., Bergman, A., . . . Karmakar, D. (2023). Magnetism in A V3Sb5 (A=Cs, Rb, and K): Origin and Consequences for the Strongly Correlated Phases. Physical Review Letters, 131(19), Article ID 196702.
Open this publication in new window or tab >>Magnetism in A V3Sb5 (A=Cs, Rb, and K): Origin and Consequences for the Strongly Correlated Phases
Show others...
2023 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 131, no 19, article id 196702Article in journal (Refereed) Published
Abstract [en]

The V-based kagome systems AV3Sb5 (A=Cs, Rb, and K) are unique by virtue of the intricate interplay of nontrivial electronic structure, topology, and intriguing fermiology, rendering them to be a playground of many mutually dependent exotic phases like charge-order and superconductivity. Despite numerous recent studies, the interconnection of magnetism and other complex collective phenomena in these systems has yet not arrived at any conclusion. Using first-principles tools, we demonstrate that their electronic structures, complex fermiologies and phonon dispersions are strongly influenced by the interplay of dynamic electron correlations, nontrivial spin-polarization and spin-orbit coupling. An investigation of the first-principles-derived intersite magnetic exchanges with the complementary analysis of q dependence of the electronic response functions and the electron-phonon coupling indicate that the system conforms as a frustrated spin cluster, where the occurrence of the charge-order phase is intimately related to the mechanism of electron-phonon coupling, rather than the Fermi-surface nesting.

Place, publisher, year, edition, pages
American Physical Society (APS), 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-340287 (URN)10.1103/PhysRevLett.131.196702 (DOI)001155751900003 ()38000423 (PubMedID)2-s2.0-85177068595 (Scopus ID)
Note

QC 20231201

Available from: 2023-12-01 Created: 2023-12-01 Last updated: 2024-02-29Bibliographically approved
Karmakar, D., Pereiro, M., Hasan, M. N., Bharati, R., Hellsvik, J., Delin, A., . . . Eriksson, O. (2023). Magnetism in A V3Sb5 (A=Cs, Rb, K): Complex landscape of dynamical magnetic textures. Physical Review B, 108(17), Article ID 174413.
Open this publication in new window or tab >>Magnetism in A V3Sb5 (A=Cs, Rb, K): Complex landscape of dynamical magnetic textures
Show others...
2023 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 108, no 17, article id 174413Article in journal (Refereed) Published
Abstract [en]

We have investigated the dynamical magnetic properties of the V-based kagome stibnite compounds by combining the ab initio-extracted magnetic parameters of a spin-Hamiltonian, like inter-site exchange parameters, magnetocrystalline anisotropy and site projected magnetic moments, with full-fledged simulations of atomistic spin- dynamics. Our calculations reveal that, in addition to a ferromagnetic order along the [001] direction, the system hosts a complex landscape of magnetic configurations comprised of commensurate and incommensurate spin spirals along the [010] direction. The presence of such chiral magnetic textures may be the key toward solving the mystery about the origin of the experimentally observed inherent breaking of the C6 rotational, mirror, and the time-reversal symmetry.

Place, publisher, year, edition, pages
American Physical Society (APS), 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-340288 (URN)10.1103/PhysRevB.108.174413 (DOI)001101171600002 ()2-s2.0-85177045826 (Scopus ID)
Note

QC 20231201

Available from: 2023-12-01 Created: 2023-12-01 Last updated: 2024-02-29Bibliographically approved
Xu, Q., Miranda, I. P., Pereiro, M., Rybakov, F. N., Thonig, D., Sjoeqvist, E., . . . Delin, A. (2023). Metaheuristic conditional neural network for harvesting skyrmionic metastable states. Physical Review Research, 5(4), Article ID 043199.
Open this publication in new window or tab >>Metaheuristic conditional neural network for harvesting skyrmionic metastable states
Show others...
2023 (English)In: Physical Review Research, E-ISSN 2643-1564, Vol. 5, no 4, article id 043199Article in journal (Refereed) Published
Abstract [en]

We present a metaheuristic conditional neural-network-based method aimed at identifying physically interest-ing metastable states in a potential energy surface of high rugosity. To demonstrate how this method works, we identify and analyze spin textures with topological charge Q ranging from 1 to -13 (where antiskyrmions have Q < 0) in the Pd/Fe/Ir(111) system, which we model using a classical atomistic spin Hamiltonian based on parameters computed from density functional theory. To facilitate the harvest of relevant spin textures, we make use of the newly developed segment anything model. Spin textures with Q ranging from -3 to -6 are further analyzed using finite-temperature spin-dynamics simulations. We observe that for temperatures up to around 20 K, lifetimes longer than 200 ps are predicted, and that when these textures decay, new topological spin textures are formed. We also find that the relative stability of the spin textures depend linearly on the topological charge, but only when comparing the most stable antiskyrmions for each topological charge. In general, the number of holes (i.e., non-self-intersecting curves that define closed domain walls in the structure) in the spin texture is an important predictor of stability-the more holes, the less stable the texture. Methods for systematic identification and characterization of complex metastable skyrmionic textures-such as the one demonstrated here-are highly relevant for advancements in the field of topological spintronics.

Place, publisher, year, edition, pages
American Physical Society (APS), 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-344103 (URN)10.1103/PhysRevResearch.5.043199 (DOI)001128824200002 ()2-s2.0-85179004348 (Scopus ID)
Note

QC 20240301

Available from: 2024-03-01 Created: 2024-03-01 Last updated: 2024-03-01Bibliographically approved
Ryan, S. A., Johnsen, P. C., Elhanoty, M. F., Grafov, A., Li, N., Delin, A., . . . Murnane, M. M. (2023). Optically controlling the competition between spin flips and intersite spin transfer in a Heusler half-metal on sub-100-fs time scales. Science Advances, 9(45), 1428
Open this publication in new window or tab >>Optically controlling the competition between spin flips and intersite spin transfer in a Heusler half-metal on sub-100-fs time scales
Show others...
2023 (English)In: Science Advances, E-ISSN 2375-2548, Vol. 9, no 45, p. 1428-Article in journal (Refereed) Published
Abstract [en]

The direct manipulation of spins via light may provide a path toward ultrafast energy-efficient devices. However, distinguishing the microscopic processes that can occur during ultrafast laser excitation in magnetic alloys is challenging. Here, we study the Heusler compound Co2MnGa, a material that exhibits very strong light-induced spin transfers across the entire M-edge. By combining the element specificity of extreme ultraviolet high-harmonic probes with time-dependent density functional theory, we disentangle the competition between three ultrafast light-induced processes that occur in Co2MnGa: same-site Co-Co spin transfer, intersite Co-Mn spin transfer, and ultrafast spin flips mediated by spin-orbit coupling. By measuring the dynamic magnetic asymmetry across the entire M-edges of the two magnetic sublattices involved, we uncover the relative dominance of these processes at different probe energy regions and times during the laser pulse. Our combined approach enables a comprehensive microscopic interpretation of laser-induced magnetization dynamics on time scales shorter than 100 femtoseconds.

Place, publisher, year, edition, pages
American Association for the Advancement of Science (AAAS), 2023
National Category
Condensed Matter Physics Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-340110 (URN)10.1126/sciadv.adi1428 (DOI)001142520500002 ()37948525 (PubMedID)2-s2.0-85176433605 (Scopus ID)
Note

QC 20231128

Available from: 2023-11-28 Created: 2023-11-28 Last updated: 2024-02-21Bibliographically approved
Chareev, D. A., Khan, M. E., Karmakar, D., Nekrasov, A. N., Nickolsky, M. S., Eriksson, O., . . . Abdel-Hafiez, M. (2023). Stable Sulfuric Vapor Transport and Liquid Sulfur Growth on Transition Metal Dichalcogenides. Crystal Growth & Design, 23(4), 2287-2294
Open this publication in new window or tab >>Stable Sulfuric Vapor Transport and Liquid Sulfur Growth on Transition Metal Dichalcogenides
Show others...
2023 (English)In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 23, no 4, p. 2287-2294Article in journal (Refereed) Published
Abstract [en]

Transition metal dichalcogenides (TMDs) are an emergent class of low-dimensional materials with growing applications in the field of nanoelectronics. However, efficient methods for synthesizing large monocrystals of these systems are still lacking. Here, we describe an efficient synthetic route for a large number of TMDs that were obtained in quartz glass ampoules by sulfuric vapor transport and liquid sulfur. Unlike the sublimation technique, the metal enters the gas phase in the form of molecules, hence containing a greater amount of sulfur than the growing crystal. We have investigated the physical properties for a selection of these crystals and compared them to state-of-the-art findings reported in the literature. The acquired electronic properties features demonstrate the overall high quality of single crystals grown in this work as exemplified by CoS2, ReS2, NbS2, and TaS2. This new approach to synthesize high-quality TMD single crystals can alleviate many material quality concerns and is suitable for emerging electronic devices.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-330970 (URN)10.1021/acs.cgd.2c01318 (DOI)000955393900001 ()37038405 (PubMedID)2-s2.0-85151269182 (Scopus ID)
Note

Correction in DOI 10.1021/acs.cgd.3c00436

QC 20230705

Available from: 2023-07-05 Created: 2023-07-05 Last updated: 2023-09-05Bibliographically approved
Azimi-Mousolou, V., Bergman, A., Delin, A., Eriksson, O., Pereiro, M., Thonig, D. & Sjöqvist, E. (2023). Transmon probe for quantum characteristics of magnons in antiferromagnets. Physical Review B, 108(9), Article ID 094430.
Open this publication in new window or tab >>Transmon probe for quantum characteristics of magnons in antiferromagnets
Show others...
2023 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 108, no 9, article id 094430Article in journal (Refereed) Published
Abstract [en]

The detection of magnons and their quantum properties, especially in antiferromagnetic (AFM) materials, is a substantial step to realize many ambitious advances in the study of nanomagnetism and the development of energy efficient quantum technologies. The recent development of hybrid systems based on superconducting circuits provides the possibility to engineer quantum sensors that exploit different degrees of freedom. Here, we examine the magnon-photon-transmon hybridization based on bipartite AFM materials, which gives rise to an effective coupling between a transmon qubit and magnons in a bipartite AFM. We demonstrate how magnon modes, their chiralities, and quantum properties, such as nonlocality and two-mode magnon entanglement in bipartite AFMs, can be characterized through the Rabi frequency of the superconducting transmon qubit.

Place, publisher, year, edition, pages
American Physical Society (APS), 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-338392 (URN)10.1103/PhysRevB.108.094430 (DOI)001080546200001 ()2-s2.0-85172422970 (Scopus ID)
Note

QC 20231024

Available from: 2023-10-24 Created: 2023-10-24 Last updated: 2023-10-31Bibliographically approved
Liu, Y., Bergman, A., Bagrov, A., Delin, A., Thonig, D., Pereiro, M., . . . Azimi-Mousolou, V. (2023). Tunable phonon-driven magnon-magnon entanglement at room temperature. New Journal of Physics, 25(11), Article ID 113032.
Open this publication in new window or tab >>Tunable phonon-driven magnon-magnon entanglement at room temperature
Show others...
2023 (English)In: New Journal of Physics, E-ISSN 1367-2630, Vol. 25, no 11, article id 113032Article in journal (Refereed) Published
Abstract [en]

We report the existence of entangled steady-states in bipartite quantum magnonic systems at elevated temperatures. We consider dissipative dynamics of two magnon modes in a bipartite antiferromagnet, subjected to interaction with a phonon mode and an external rotating magnetic field. To quantify the bipartite magnon-magnon entanglement, we use entanglement negativity and compute its dependence on temperature and magnetic field. We provide evidence that the coupling between magnon and phonon modes is necessary for the entanglement, and that, for any given phonon frequency and magnon-phonon coupling rate, there are always ranges of the magnetic field amplitudes and frequencies for which magnon-magnon entanglement persists at room temperature.

Place, publisher, year, edition, pages
IOP Publishing, 2023
Keywords
magnon, phonon, steady-state, quantum entanglement, room temperature
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-340446 (URN)10.1088/1367-2630/ad0b20 (DOI)001104537600001 ()2-s2.0-85178149802 (Scopus ID)
Note

QC 20231205

Available from: 2023-12-05 Created: 2023-12-05 Last updated: 2024-01-17Bibliographically approved
Cardias, R., Silva, J. d., Bergman, A., Szilva, A., Kvashnin, Y. O., Fransson, J., . . . Nordström, L. (2023). Unraveling the connection between high-order magnetic interactions and local-to-global spin Hamiltonian in noncollinear magnetic dimers. Physical Review B, 108(22), Article ID 224408.
Open this publication in new window or tab >>Unraveling the connection between high-order magnetic interactions and local-to-global spin Hamiltonian in noncollinear magnetic dimers
Show others...
2023 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 108, no 22, article id 224408Article in journal (Refereed) Published
Abstract [en]

A spin Hamiltonian that characterizes interatomic interactions between spin moments is highly valuable in predicting and comprehending the magnetic properties of materials. Here, we explore a method for explicitly calculating interatomic exchange interactions in noncollinear configurations of magnetic materials considering only a bilinear spin Hamiltonian in a local scenario. Based on density-functional theory calculations of dimers adsorbed on metallic surfaces, and with a focus on the Dzyaloshinskii-Moriya interaction (DMI) which is essential for stabilizing chiral noncollinear magnetic states, we discuss the interpretation of the DMI when decomposed into microscopic electron and spin densities and currents. We clarify the distinct origins of spin currents induced in the system and their connection to the DMI. In addition, we reveal how noncollinearity affects the usual DMI, which is solely induced by spin-orbit coupling, and DMI-like interactions brought about by noncollinearity. We explain how the dependence of the DMI on the magnetic configuration establishes a connection between high-order magnetic interactions, enabling the transition from a local to a global spin Hamiltonian.

Place, publisher, year, edition, pages
American Physical Society (APS), 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-341598 (URN)10.1103/PhysRevB.108.224408 (DOI)001141676300006 ()2-s2.0-85179475159 (Scopus ID)
Note

QC 20231227

Available from: 2023-12-27 Created: 2023-12-27 Last updated: 2024-02-29Bibliographically approved
Projects
Ultrafast Magnonics [2022-02881_VR]; Uppsala University
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7788-6127

Search in DiVA

Show all publications