arXiv - PHYS - Other Condensed Matter最新文献_第7页

Differential phase contrast from electrons that cause inner shell ionization 引起内壳电离的电子产生的差分相位对比

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-15 DOI: arxiv-2405.09043

Michael Deimetry, Timothy C. Petersen, Hamish G. Brown, Matthew Weyland, Scott D. Findlay

{"title":"Differential phase contrast from electrons that cause inner shell ionization","authors":"Michael Deimetry, Timothy C. Petersen, Hamish G. Brown, Matthew Weyland, Scott D. Findlay","doi":"arxiv-2405.09043","DOIUrl":"https://doi.org/arxiv-2405.09043","url":null,"abstract":"Differential Phase Contrast (DPC) imaging, in which deviations in the bright\u0000field beam are in proportion to the electric field, has been extensively\u0000studied in the context of pure elastic scattering. Here we discuss differential\u0000phase contrast formed from core-loss scattered electrons, i.e. those that have\u0000caused inner shell ionization of atoms in the specimen, using a transition\u0000potential approach for which we study the convergence properties. In the phase\u0000object approximation, we show formally that this is mainly a result of\u0000preservation of elastic contrast. Through simulation we demonstrate that\u0000whether the inelastic DPC images show element selective contrast depends on the\u0000spatial range of the ionization interaction, and specifically that when the\u0000energy loss is low the delocalisation can lead to contributions to the contrast\u0000from atoms other than that ionized. We further show that inelastic DPC images\u0000remain robustly interpretable to larger thicknesses than is the case for\u0000elastic DPC images, owing to the incoherence of the inelastic wavefields,\u0000though subtleties due to channelling remain.","PeriodicalId":501211,"journal":{"name":"arXiv - PHYS - Other Condensed Matter","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141059885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Electric-field gradients at the nuclei from all-electron, four-component relativistic density-functional theory using Gaussian-type orbitals 利用高斯轨道的全电子四分量相对论密度函数理论得出的原子核电场梯度

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-13 DOI: arxiv-2405.07832

Marc Joosten, Michal Repisky, Marius Kadek, Pekka Pyykkö, Kenneth Ruud

{"title":"Electric-field gradients at the nuclei from all-electron, four-component relativistic density-functional theory using Gaussian-type orbitals","authors":"Marc Joosten, Michal Repisky, Marius Kadek, Pekka Pyykkö, Kenneth Ruud","doi":"arxiv-2405.07832","DOIUrl":"https://doi.org/arxiv-2405.07832","url":null,"abstract":"We present an all-electron, four-component relativistic implementation of\u0000electric field gradients (EFGs) at the nuclei using Gaussian-type orbitals and\u0000periodic boundary conditions. This allows us to include relativistic effects\u0000variationally, which is important for compounds containing heavy elements and\u0000for a property dependent the electronic structure close to the nuclei. The\u0000all-electron approach ensures an accurate treatment of both core and valence\u0000orbitals, as both are important in the evaluation of EFGs. Computational\u0000efficiency is achieved through the use of a recent implementation of density\u0000fitting in combination with quaternion algebra and restricted kinetic balance.\u0000We use the relativistic approach to calculate the EFGs in different arsenic,\u0000antimony and bismuth halides and oxyhalides, and explore the importance of\u0000relativistic effects on EFGs in solids and compare these with results obtained\u0000for molecular species. Our calculations contribute to establishing a reliable\u0000estimate for the nuclear quadrupole moment of 209Bi, for which our best\u0000estimate is -428(17) mb, in excellent agreement both with molecular data and a\u0000recent reevaluation of the nuclear quadrupole moment obtained from atomic data\u0000and ab initio calculations. Our results suggest that there is a need to revisit\u0000the experimental data for the EFGs of several bismuth oxyhalides.","PeriodicalId":501211,"journal":{"name":"arXiv - PHYS - Other Condensed Matter","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Wide energy range cross section of elastic electron scattering in matter: dependence of dynamical screening of target atoms on electron velocity 物质中弹性电子散射的宽能程截面：靶原子的动态筛选与电子速度的关系

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-11 DOI: arxiv-2405.06950

N. Medvedev, D. I. Zainutdinov, A. E. Volkov

引用次数: 0

Fitting to magnetic forces improves the reliability of magnetic Moment Tensor Potentials 与磁力拟合提高了磁矩张势的可靠性

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-11 DOI: arxiv-2405.07069

Alexey S. Kotykhov, Konstantin Gubaev, Vadim Sotskov, Christian Tantardini, Max Hodapp, Alexander V. Shapeev, Ivan S. Novikov

{"title":"Fitting to magnetic forces improves the reliability of magnetic Moment Tensor Potentials","authors":"Alexey S. Kotykhov, Konstantin Gubaev, Vadim Sotskov, Christian Tantardini, Max Hodapp, Alexander V. Shapeev, Ivan S. Novikov","doi":"arxiv-2405.07069","DOIUrl":"https://doi.org/arxiv-2405.07069","url":null,"abstract":"We propose a novel method for fitting machine-learning interatomic potentials\u0000with magnetic degrees of freedom, namely, magnetic Moment Tensor Potentials\u0000(mMTP). The main feature of the methodology consists in fitting mMTP to\u0000magnetic forces (negative derivatives of energies with respect to magnetic\u0000moments) derived from spin-polarized density functional theory calculations. We\u0000test our method on the bcc Fe-Al system with different composition.\u0000Specifically, we calculate formation energies, equilibrium lattice parameter,\u0000and total cell magnetization. Our findings demonstrate a precise match between\u0000values calculated with mMTP and those obtained by DFT at zero temperature.\u0000Additionally, using molecular dynamics, we estimate the finite temperature\u0000lattice parameter and capture the cell expansion as was previously revealed in\u0000experiment. We demonstrate that mMTPs fitted to magnetic forces, increase the\u0000relaxation reliability, which is the percent of successfully relaxed structures\u0000(i.e. with almost zero forces, stresses, and magnetic moments after the\u0000optimization of geometry). Eventually, we show that the proposed methodology\u0000can provide an accurate and reliable mMTP with reduced number of\u0000computationally complex spin-polarized density functional theory calculations.","PeriodicalId":501211,"journal":{"name":"arXiv - PHYS - Other Condensed Matter","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantum State Transfer in Interacting, Multiple-Excitation Systems 相互作用、多重激发系统中的量子态转移

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-10 DOI: arxiv-2405.06853

Alexander Yue, Rubem Mondaini, Qiujiang Guo, Richard T. Scalettar

引用次数: 0

Altermagnetic Polar Metallic phase in Ultra-Thin Epitaxially-Strained RuO2 Films 超薄外延应变 RuO2 薄膜中的异磁极金属相

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-09 DOI: arxiv-2405.05838

Seung Gyo Jeong, In Hyeok Choi, Sreejith Nair, Luca Buiarelli, Bita Pourbahari, Jin Young Oh, Nabil Bassim, Ambrose Seo, Woo Seok Choi, Rafael M. Fernandes, Turan Birol, Liuyan Zhao, Jong Seok Lee, Bharat Jalan

{"title":"Altermagnetic Polar Metallic phase in Ultra-Thin Epitaxially-Strained RuO2 Films","authors":"Seung Gyo Jeong, In Hyeok Choi, Sreejith Nair, Luca Buiarelli, Bita Pourbahari, Jin Young Oh, Nabil Bassim, Ambrose Seo, Woo Seok Choi, Rafael M. Fernandes, Turan Birol, Liuyan Zhao, Jong Seok Lee, Bharat Jalan","doi":"arxiv-2405.05838","DOIUrl":"https://doi.org/arxiv-2405.05838","url":null,"abstract":"Altermagnetism refers to a wide class of compensated magnetic orders\u0000featuring magnetic sublattices with opposite spins related by rotational\u0000symmetry rather than inversion or translational operations, resulting in\u0000non-trivial spin splitting and high-order multipolar orders. Here, by combining\u0000theoretical analysis, electrical transport, X-ray and optical spectroscopies,\u0000and nonlinear optical measurements, we establish a phase diagram in hybrid\u0000molecular beam epitaxy-grown RuO2/TiO2 (110) films, mapping the broken\u0000symmetries along the altermagnetic/electronic/structural phase transitions as\u0000functions of film thickness and temperature. This phase diagram features a\u0000novel altermagnetic metallic polar phase in strained 2 nm samples, extending\u0000the concept of multiferroics to altermagnetic systems. These results provide a\u0000comprehensive understanding of altermagnetism upon epitaxial heterostructure\u0000design for emergent novel phases with multifunctionalities.","PeriodicalId":501211,"journal":{"name":"arXiv - PHYS - Other Condensed Matter","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Recycling failed photoelectrons via tertiary photoemission 通过三次光发射回收失效光电子

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-09 DOI: arxiv-2405.06141

M. Matzelle, Wei-Chi Chiu, Caiyun Hong, Barun Ghosh, Pengxu Ran, R. S. Markiewicz, B. Barbiellini, Changxi Zheng, Sheng Li, Rui-Hua He, Arun Bansil

{"title":"Recycling failed photoelectrons via tertiary photoemission","authors":"M. Matzelle, Wei-Chi Chiu, Caiyun Hong, Barun Ghosh, Pengxu Ran, R. S. Markiewicz, B. Barbiellini, Changxi Zheng, Sheng Li, Rui-Hua He, Arun Bansil","doi":"arxiv-2405.06141","DOIUrl":"https://doi.org/arxiv-2405.06141","url":null,"abstract":"A key insight of Einstein's theory of the photoelectric effect is that a\u0000minimum energy is required for photoexcited electrons to escape from a\u0000material. For the past century it has been assumed that photoexcited electrons\u0000of lower energies make no contribution to the photoemission spectrum. Here we\u0000demonstrate the conceptual possibility that the energy of these 'failed'\u0000photoelectrons-primary or secondary-can be partially recycled to generate new\u0000'tertiary' electrons of energy sufficient to escape. Such a 'recycling' step\u0000goes beyond the traditional three steps of the photoemission process\u0000(excitation, transport, and escape), and, as we illustrate, it can be realized\u0000through a novel Auger mechanism that involves three distinct minority\u0000electronic states in the material. We develop a phenomenological three-band\u0000model to treat this mechanism within a revised four-step framework for\u0000photoemission, which contains robust features of linewidth narrowing and\u0000population inversion under strong excitation, reminiscent of the lasing\u0000phenomena. We show that the conditions for this recycling mechanism are likely\u0000satisfied in many quantum materials with multiple flat bands properly located\u0000away from the Fermi level, and elaborate on the representative case of SrTiO3\u0000among other promising candidates. We further discuss how this mechanism can\u0000explain the recent observation of anomalous intense coherent photoemission from\u0000a SrTiO3 surface, and predict its manifestations in related experiments,\u0000including the 'forbidden' case of photoemission with photon energies lower than\u0000the work function. Our study calls for paradigm shifts across a range of\u0000fundamental and applied research fields, especially in the areas of\u0000photoemission, photocathodes, and flat-band materials.","PeriodicalId":501211,"journal":{"name":"arXiv - PHYS - Other Condensed Matter","volume":"127 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Magnetic Ordering of Ammonium Cations in NH$_4$I, NH$_4$Br and NH$_4$Cl NH$_4$I、NH$_4$Br 和 NH$_4$Cl 中铵阳离子的磁有序性

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-06 DOI: arxiv-2405.03163

Fei Yen, Lei Meng, Tian Gao, Sixia Hu

引用次数: 0

The influence of dark excitons on the electroabsorption spectrum of polyacetylene 暗激子对聚乙炔电吸收光谱的影响

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-05 DOI: arxiv-2405.03012

Jaspal Singh Bola, Ryan M. Stolley, Prashanna Poudel, Joel S. Miller, Christoph Boheme, Z. Valy Vardeny

{"title":"The influence of dark excitons on the electroabsorption spectrum of polyacetylene","authors":"Jaspal Singh Bola, Ryan M. Stolley, Prashanna Poudel, Joel S. Miller, Christoph Boheme, Z. Valy Vardeny","doi":"arxiv-2405.03012","DOIUrl":"https://doi.org/arxiv-2405.03012","url":null,"abstract":"This study revisits the electroabsorption (EA) spectrum of polyacetylene, as\u0000functions of the electric field strength, isomerization degree, and light\u0000polarization states. The EA spectrum of $cis$-$(CH)_x$ reveals an oscillatory\u0000feature that follows the Stark shift-related first derivative of the materials\u0000absorption spectrum that contains v(0-1) and v(0-2) sidebands of the excited\u0000$C=C$ stretching vibration that agrees well with the Raman spectrum. EA\u0000spectrum of $trans $-$(CH)_x$ does not match the first derivative of the\u0000materials absorption spectrum, and the phonon sideband frequency does not agree\u0000with the RS spectrum. EA spectrum of $trans $-$(CH)_x$ reveals a band below the\u0000first allowed $1B_u$ exciton. We interpret this feature as due to the electric\u0000field activated even-parity dark (forbidden) exciton, namely $mA_g$ ($m >1$),\u0000showing that the nonluminescent $trans $-$(CH)_x$ is due to the reverse order\u0000of the excited states, where a dark $mA_g$ exciton lies below the allowed\u0000$1B_u$ exciton. This agrees with the unusual phonon sideband in $trans\u0000$-$(CH)_x$ absorption, since the excited state attenuation caused by the fast\u0000internal conversion from $1B_u$ to $mA_g$ influences the apparent frequency\u0000that determines the phonon sideband. Consequently, from the EA and RS spectra\u0000we estimate the $1B_u$ lifetime in $trans $-$(CH)_x$ to be $sim 30$ fs.\u0000Integrated EA spectrum of $trans $-$(CH)_x$ shows a traditional Huang-Rhys type\u0000series with a relaxation parameter, $S sim 0.5$. This indicates that the EA\u0000spectrum of the $trans $ isomer is also determined by a Stark shift related to\u0000the first derivative of the absorption spectrum, but preferentially for the\u0000longest chains in the films chain lengths distribution. This is due to the\u0000$N^3$ response of the non-linear susceptibility, $chi^{(3)}$ ($sim$EA),\u0000dependence on the chain length having $N$ monomers.","PeriodicalId":501211,"journal":{"name":"arXiv - PHYS - Other Condensed Matter","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Python code for calculating the mean-value (Baldereschi's) point for any crystal structure Python 代码，用于计算任何晶体结构的平均值（Baldereschi's）点

arXiv - PHYS - Other Condensed Matter Pub Date : 2024-05-02 DOI: arxiv-2405.00925

Vladan Stevanovic

引用次数: 0