Structural Dynamics-Us最新文献_第7页

Femtosecond charge and spin dynamics in a Co₅₀Pt₅₀ alloy. Co50Pt50合金飞秒电荷和自旋动力学。

IF 2.9 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-04-25 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000297

Martin Pavelka, Simon Marotzke, Ru-Pan Wang, Mohamed F Elhanoty, Günter Brenner, Siarhei Dziarzhytski, Somnath Jana, W Dieter Engel, Clemens V Korff Schmising, Deeksha Gupta, Igor Vaskivskyi, Tim Amrhein, Nele Thielemann-Kühn, Martin Weinelt, Ronny Knut, Juliane Rönsch-Schulenberg, Evgeny Schneidmiller, Christian Schüßler-Langeheine, Martin Beye, Niko Pontius, Oscar Grånäs, Hermann A Dürr

{"title":"Femtosecond charge and spin dynamics in a Co50Pt50 alloy.","authors":"Martin Pavelka, Simon Marotzke, Ru-Pan Wang, Mohamed F Elhanoty, Günter Brenner, Siarhei Dziarzhytski, Somnath Jana, W Dieter Engel, Clemens V Korff Schmising, Deeksha Gupta, Igor Vaskivskyi, Tim Amrhein, Nele Thielemann-Kühn, Martin Weinelt, Ronny Knut, Juliane Rönsch-Schulenberg, Evgeny Schneidmiller, Christian Schüßler-Langeheine, Martin Beye, Niko Pontius, Oscar Grånäs, Hermann A Dürr","doi":"10.1063/4.0000297","DOIUrl":"10.1063/4.0000297","url":null,"abstract":"The use of advanced x-ray sources plays a key role in the study of dynamic processes in magnetically ordered materials. The progress in x-ray free-electron lasers enables the direct and simultaneous observation of the femtosecond evolution of electron and spin systems through transient x-ray absorption spectroscopy and x-ray magnetic circular dichroism, respectively. Such experiments allow us to resolve the response seen in the population of the spin-split valence states upon optical excitation. Here, we utilize circularly polarized ultrashort soft x-ray pulses from the new helical afterburner undulator at the free-electron laser FLASH in Hamburg to study the femtosecond dynamics of a laser-excited CoPt alloy at the Co L3-edge absorption. Despite employing a weaker electronic excitation level, we find a comparable demagnetization for the Co 3d-states in CoPt compared to previous measurements on CoPd. This is attributed to the distinctly different spin-orbit coupling between 3d and 4d vs 3d and 5d elements in the corresponding alloys and multilayers.","PeriodicalId":48683,"journal":{"name":"Structural Dynamics-Us","volume":"12 2","pages":"024303"},"PeriodicalIF":2.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12033042/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144020103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Defects in magnetic domain walls after single-shot all-optical switching. 单次全光开关后磁畴壁缺陷。

IF 2.9 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-04-18 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000287

Daniel Metternich, Kai Litzius, Sebastian Wintz, Kathinka Gerlinger, Sascha Petz, Dieter Engel, Themistoklis Sidiropoulos, Riccardo Battistelli, Felix Steinbach, Markus Weigand, Steffen Wittrock, Clemens von Korff Schmising, Felix Büttner

{"title":"Defects in magnetic domain walls after single-shot all-optical switching.","authors":"Daniel Metternich, Kai Litzius, Sebastian Wintz, Kathinka Gerlinger, Sascha Petz, Dieter Engel, Themistoklis Sidiropoulos, Riccardo Battistelli, Felix Steinbach, Markus Weigand, Steffen Wittrock, Clemens von Korff Schmising, Felix Büttner","doi":"10.1063/4.0000287","DOIUrl":"10.1063/4.0000287","url":null,"abstract":"Helicity-independent all-optical switching (HI-AOS) is the fastest known way to switch the magnetic order parameter. While the switching process of extended areas is well understood, the formation of domain walls enclosing switched areas remains less explored. Here, we study domain walls around all-optically nucleated magnetic domains using x-ray vector spin imaging and observe a high density of vertical Bloch line defects. Surprisingly, the defect density appears to be independent of optical pulse parameters, significantly varies between materials, and is only slightly higher than in domain walls generated by field cycling. A possible explanation is given by time-resolved Kerr microscopy, which reveals that magnetic domains considerably expand after the initial AOS process. During this expansion, and likewise during field cycling, domain walls propagate at speeds above the Walker breakdown. Micromagnetic simulations suggest that at such speeds, domain walls accumulate defects when moving over magnetic pinning sites, explaining similar defect densities after two very different switching processes. The slightly larger defect density after AOS compared to field-induced switching indicates that some defects are created already when the domain wall comes into existence. Our work shows that engineered low-pinning materials are a key ingredient to uncover the intrinsic dynamics of domain wall formation during ultrafast all-optical switching.","PeriodicalId":48683,"journal":{"name":"Structural Dynamics-Us","volume":"12 2","pages":"024504"},"PeriodicalIF":2.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12009145/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144020100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unraveling atomic complexity from frozen samples. 从冷冻样品中揭示原子复杂性。

IF 2.3 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-04-18 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000303

Yasmeen N Ruma, Brent L Nannenga, Tamir Gonen

引用次数: 0

A new chapter for RCSB Protein Data Bank Molecule of the Month in 2025. 2025年RCSB蛋白质数据库月度分子的新篇章。

IF 2.9 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-04-18 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000302

Janet Iwasa, David S Goodsell, Stephen K Burley, Christine Zardecki

引用次数: 0

Characterization of the photoelectron circular dichroism of fixed-in-space molecules through an asymmetry of the ionic potential. 通过离子势的不对称性表征空间固定分子的光电子圆二色性。

IF 2.3 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-04-18 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000300

Eric Kutscher, Anton N Artemyev, Philipp V Demekhin

{"title":"Characterization of the photoelectron circular dichroism of fixed-in-space molecules through an asymmetry of the ionic potential.","authors":"Eric Kutscher, Anton N Artemyev, Philipp V Demekhin","doi":"10.1063/4.0000300","DOIUrl":"https://doi.org/10.1063/4.0000300","url":null,"abstract":"Photoelectron circular dichroism (PECD) in the ionization of chiral molecules by circularly polarized radiation is a well-established tool for chiral recognition in the gas phase. The effect consists in a forward-backward asymmetry in angular emission distributions of photoelectrons with respect to the light propagation direction, which survives averaging over molecular orientations. Its magnitude is governed by the ability of the outgoing photoelectron to probe an asymmetry of the ionic potential by multiple scattering effects, and it can be significantly enhanced by fixing molecular orientation in space. Even achiral fixed-in-space molecules can exhibit such a forward-backward asymmetry in the photoemission. In the present work, we establish a qualitative correspondence between the PECD in one-photon ionization of fixed-in-space molecules and a degree of the asymmetry of their ionic potential. For this purpose, we introduce an enantiosensitive dichroic characteristic of the ionic potential, which describes a physical mechanism behind the forward-backward asymmetry in the photoemission from fixed-in-space molecules ionized by circularly polarized light. This characteristic, as a function of molecular orientation angles, can be compared to the respective PECD landscape. The present findings are exemplified by several applications to achiral and chiral species.","PeriodicalId":48683,"journal":{"name":"Structural Dynamics-Us","volume":"12 2","pages":"024102"},"PeriodicalIF":2.3,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12009146/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144053516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Discovery of a new zinc oxide semiconductor: 21R polytype. 一种新型氧化锌半导体的发现：21R多型。

IF 2.3 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-03-27 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000296

Matej Fonović, Jelena Zagorac, Maria Čebela, Dragana Jordanov, Dejan Zagorac

{"title":"Discovery of a new zinc oxide semiconductor: 21R polytype.","authors":"Matej Fonović, Jelena Zagorac, Maria Čebela, Dragana Jordanov, Dejan Zagorac","doi":"10.1063/4.0000296","DOIUrl":"10.1063/4.0000296","url":null,"abstract":"Zinc oxide (ZnO) is a notable semiconductor with a range of interesting electronic and optical properties. Polytypic behavior of crystal structures can strongly affect the properties of materials, especially in ZnO. We report the first prediction of a new 21R polytype in zinc oxide with advanced properties. Ab initio calculations were carried out using two-hybrid functionals: HSE06 and PBE0. Structural properties of different ZnO polytypes were investigated, and theoretical data concurred with experimental results. This can be further exploited for various applications based on their unique properties. Electronic properties were studied using band structures and density of states (DOS). Present DFT calculations agree very well with previous calculations and measurements of known ZnO polytypes, and the new 21R polytype is found as a direct band gap semiconductor. The size of the band gap in the case of the hybrid HSE06 functional is calculated to be 2.79 eV and with PBE0 is 3.42 eV. Understanding the structure-property relationship helps in tailoring ZnO for specific applications and optimizing its performance in various technological contexts, especially as an advanced semiconductor material, with possible applications such as 0D, 1D, 2D, and 3D materials.","PeriodicalId":48683,"journal":{"name":"Structural Dynamics-Us","volume":"12 2","pages":"024101"},"PeriodicalIF":2.3,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11952831/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143755285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Probing optically driven K₃C₆₀ thin films with an ultrafast voltmeter. 利用超快电压计探测光驱动 K3C60 薄膜。

IF 2.3 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-03-26 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000295

J D Adelinia, E Wang, M Chavez-Cervantes, T Matsuyama, M Fechner, M Buzzi, G Meier, A Cavalleri

{"title":"Probing optically driven K3C60 thin films with an ultrafast voltmeter.","authors":"J D Adelinia, E Wang, M Chavez-Cervantes, T Matsuyama, M Fechner, M Buzzi, G Meier, A Cavalleri","doi":"10.1063/4.0000295","DOIUrl":"10.1063/4.0000295","url":null,"abstract":"Optically enhanced superconductivity in K3C60 is supported by transient optical spectra, by pressure responses, and by ultrafast nonlinear transport measurements. However, the underlying physics and in fact the similarity or dissimilarity to most properties of equilibrium superconductivity are not clear. In this paper, we study the ultrafast voltage response of optically driven K3C60 thin films. Photo-conductive switches are used to measure changes in voltage as a function of time after irradiation, both below and above Tc. These measurements can be understood if one considers the role of granularity in the photo-induced transport response. They reveal fast voltage changes associated with the kinetic inductance of the in-grain carriers and a slower response that may be attributed to Josephson dynamics at the weak links. Fits to the data yield estimates of the in-grain photo-induced superfluid density after the drive and the dynamics of phase slips at the weak links. This work underscores the increasing ability to make electrical measurements at ultrafast speeds in optically driven quantum materials and demonstrates a striking new platform for optoelectronic device applications.","PeriodicalId":48683,"journal":{"name":"Structural Dynamics-Us","volume":"12 2","pages":"024503"},"PeriodicalIF":2.3,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11949515/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143732695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Magnetization dynamics: From the Landau-Lifschitz equation to spintronics. 磁化动力学：从朗道-利夫希茨方程到自旋电子学。

IF 2.3 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-03-25 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000290

Yves Acremann

引用次数: 0

Simultaneous mapping of the ultrafast time and fluence dependence of the laser-induced insulator-to-metal transition in magnetite. 磁铁矿中激光诱导绝缘体到金属跃迁的超快时间和通量依赖关系的同步映射。

IF 2.3 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-03-20 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000288

J O Schunck, P S Miedema, R Y Engel, S Dziarzhytski, G Brenner, N Ekanayake, C-F Chang, P Bougiatioti, F Döring, B Rösner, C David, C Schüßler-Langeheine, M Beye

{"title":"Simultaneous mapping of the ultrafast time and fluence dependence of the laser-induced insulator-to-metal transition in magnetite.","authors":"J O Schunck, P S Miedema, R Y Engel, S Dziarzhytski, G Brenner, N Ekanayake, C-F Chang, P Bougiatioti, F Döring, B Rösner, C David, C Schüßler-Langeheine, M Beye","doi":"10.1063/4.0000288","DOIUrl":"10.1063/4.0000288","url":null,"abstract":"Pump-probe methods are a ubiquitous tool in the field of ultrafast dynamic measurements. In recent years, x-ray free-electron laser experiments have gained importance due to their ability to probe with high chemical selectivity and at atomic length scales. Measurements are typically repeated many thousands of times to collect sufficient statistics and vary parameters like delay or fluence, necessitating that initial conditions are restored each time. An alternative is presented by experiments which measure the relevant parameters in a single shot. Here, we present a time-to-space mapping imaging scheme that enables us to record a range of delays and laser fluences in any single shot of the x-ray probe. We demonstrate the use of this scheme by mapping the ultrafast dynamics of the optically induced insulator-to-metal Verwey transition in a magnetite thin film, probed by soft x-ray resonant diffraction. By extrapolating our results toward the conditions found at x-ray free-electron lasers with higher photon energy, we demonstrate that the presented data could be recorded in a single shot.","PeriodicalId":48683,"journal":{"name":"Structural Dynamics-Us","volume":"12 2","pages":"024302"},"PeriodicalIF":2.3,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11928099/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143694127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ultrafast-induced coherent acoustic phonons in the two-dimensional magnet CrSBr. 二维磁体 CrSBr 中的超快诱导相干声子。

IF 2.3 2区物理与天体物理

Structural Dynamics-Us Pub Date : 2025-03-20 eCollection Date: 2025-03-01 DOI: 10.1063/4.0000266

Jayajeewana N Ranhili, Sumit Khadka, Junjie Li, John Cenker, Alberto M Ruiz, Andrei Shumilin, José J Baldoví, Ka Shen, Mikhail Fedurin, Mark Palmer, Daniel G Chica, Paul Byaruhanga, Shuo Chen, Xiaodong Xu, Xavier Roy, Byron Freelon

{"title":"Ultrafast-induced coherent acoustic phonons in the two-dimensional magnet CrSBr.","authors":"Jayajeewana N Ranhili, Sumit Khadka, Junjie Li, John Cenker, Alberto M Ruiz, Andrei Shumilin, José J Baldoví, Ka Shen, Mikhail Fedurin, Mark Palmer, Daniel G Chica, Paul Byaruhanga, Shuo Chen, Xiaodong Xu, Xavier Roy, Byron Freelon","doi":"10.1063/4.0000266","DOIUrl":"10.1063/4.0000266","url":null,"abstract":"Magnetism in two-dimensional (2D) van der Waals (vdW) crystals offers promising new directions for low-dimensional physics and devices. In this work, mega-electron volt (MeV) ultrafast electron diffraction was employed to investigate the ultrafast atomic dynamics of a novel, 2D vdW magnetic single-crystal CrSBr. Femtosecond (fs) optical pump pulses excited non-equilibrium atomic displacements shown to be coherent acoustic phonons (CAPs). Phonon frequencies were extracted by analyzing oscillations of different Bragg peak (BP) intensities and were determined to be GHz acoustic disturbances that propagated as strain waves. Phonon modes exhibit anisotropy with respect to the a and b crystal axes. Subharmonic phonon frequencies were also observed, and this provided a signature of nonlinear oscillatory coupling between the laser-induced pumping phonon frequency and secondary phonon frequencies. Thus, CrSBr was found to serve as a nonlinear phononic frequency converter. The ultrafast time dependence of the Bragg intensity was simulated by incorporating an oscillating deviation parameter ansatz into expressions for the dynamical scattering intensity yielded excellent modeling of the ultrafast structural dynamics of the photo-excited 2D crystal. Our work provides a foundation for exploring how fs light pulses can influence phonon dynamics in materials with strong spin-lattice coupling. These results suggest that CAPs can match the magnon frequencies and show the promise of CrSBr for use in optical-to-microwave transducers and phononic devices.","PeriodicalId":48683,"journal":{"name":"Structural Dynamics-Us","volume":"12 2","pages":"024501"},"PeriodicalIF":2.3,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11928097/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143694050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0