首页 > 最新文献

arXiv: Mesoscale and Nanoscale Physics最新文献

英文 中文
Ultrafast creation and melting of nonequilibrium excitonic condensates in bulk WSe2 非平衡态激子凝聚体WSe2的超快生成和熔化
Pub Date : 2020-11-24 DOI: 10.1103/PhysRevB.103.L241404
E. Perfetto, G. Stefanucci
We study the screened dynamics of the nonequilibrium excitonic consensate forming in a bulk WSe$_{2}$ when illuminated by coherent light resonant with the lowest-energy exciton. Intervalley scattering causes electron migration from the optically populated K valley to the conduction band minimum at $Sigma$. Due to the electron-hole unbalance at the K point a plasma of quasi-free holes develops, which efficiently screens the interaction of the remaining excitons. We show that this plasma screening causes an ultrafast melting of the nonequilibrium consensate and that during melting coherent excitons and quasi-free electron-hole pairs coexist. The time-resolved spectral function does exhibit a conduction and excitonic sidebands of opposite convexity and relative spectral weight that changes in time. Both the dependence of the time-dependent conduction density on the laser intensity and the time-resolved spectral function agree with recent experiments.
本文研究了在以最低能量激子共振的相干光照射下,体WSe$_{2}$中非平衡激子凝聚形成的屏蔽动力学。谷间散射导致电子从光填充的K谷迁移到传导带最小值$Sigma$。由于K点的电子-空穴不平衡,产生了准自由空穴等离子体,有效地屏蔽了剩余激子的相互作用。我们发现这种等离子体筛选导致非平衡态的超快熔化,并且在熔化过程中相干激子和准自由电子-空穴对共存。时间分辨谱函数确实表现出相反凸性的传导和激子边带以及随时间变化的相对谱权。随时间变化的导通密度与激光强度的关系以及随时间变化的谱函数与最近的实验结果一致。
{"title":"Ultrafast creation and melting of nonequilibrium excitonic condensates in bulk \u0000WSe2","authors":"E. Perfetto, G. Stefanucci","doi":"10.1103/PhysRevB.103.L241404","DOIUrl":"https://doi.org/10.1103/PhysRevB.103.L241404","url":null,"abstract":"We study the screened dynamics of the nonequilibrium excitonic consensate forming in a bulk WSe$_{2}$ when illuminated by coherent light resonant with the lowest-energy exciton. Intervalley scattering causes electron migration from the optically populated K valley to the conduction band minimum at $Sigma$. Due to the electron-hole unbalance at the K point a plasma of quasi-free holes develops, which efficiently screens the interaction of the remaining excitons. We show that this plasma screening causes an ultrafast melting of the nonequilibrium consensate and that during melting coherent excitons and quasi-free electron-hole pairs coexist. The time-resolved spectral function does exhibit a conduction and excitonic sidebands of opposite convexity and relative spectral weight that changes in time. Both the dependence of the time-dependent conduction density on the laser intensity and the time-resolved spectral function agree with recent experiments.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86023041","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: 3
Simulating higher-order topological insulators in density wave insulators 密度波绝缘子中高阶拓扑绝缘子的模拟
Pub Date : 2020-11-24 DOI: 10.1103/PhysRevB.103.245107
Kuan-Sen Lin, B. Bradlyn
Since the discovery of the Harper-Hofstadter model, it has been known that condensed matter systems with periodic modulations can be promoted to non-trivial topological states with emergent gauge fields in higher dimensions. In this work, we develop a general procedure to compute the gauge fields in higher dimensions associated to low-dimensional systems with periodic (charge- and spin-) density wave modulations. We construct two-dimensional (2D) models with modulations that can be promoted to higher-order topological phases with $U(1)$ and $SU(2)$ gauge fields in 3D. Corner modes in our 2D models can be pumped by adiabatic sliding of the phase of the modulation, yielding hinge modes in the promoted models. We also examine a 3D Weyl semimetal (WSM) gapped by charge-density wave (CDW) order, possessing quantum anomalous Hall (QAH) surface states. We show that this 3D system is equivalent to a 4D nodal line system gapped by a $U(1)$ gauge field with a nonzero second Chern number. We explain the recently identified interpolation between inversion-symmetry protected phases of the 3D WSM gapped by CDWs using the corresponding 4D theory. Our results can extend the search for (higher-order) topological states in higher dimensions to density wave systems.
自从Harper-Hofstadter模型的发现以来,人们已经知道具有周期调制的凝聚态系统可以被提升到具有高维涌现规范场的非平凡拓扑状态。在这项工作中,我们开发了一个通用的程序来计算与具有周期性(电荷和自旋)密度波调制的低维系统相关的高维规范场。我们构建了具有调制的二维(2D)模型,该模型可以在3D中提升到具有$U(1)$和$SU(2)$规范域的高阶拓扑相位。我们的二维模型中的角模可以通过调制相位的绝热滑动来泵浦,从而产生提升模型中的铰链模。我们还研究了一种具有量子异常霍尔(QAH)表面态的三维Weyl半金属(WSM),这种金属是由电荷密度波(CDW)顺序间隙形成的。我们证明了该三维系统等价于一个由$U(1)$规范域间隔的具有非零秒陈数的4D节点线系统。我们用相应的四维理论解释了最近发现的由CDWs间隙的三维WSM的逆对称保护相位之间的插值。我们的结果可以将高维(高阶)拓扑状态的搜索扩展到密度波系统。
{"title":"Simulating higher-order topological insulators in density wave insulators","authors":"Kuan-Sen Lin, B. Bradlyn","doi":"10.1103/PhysRevB.103.245107","DOIUrl":"https://doi.org/10.1103/PhysRevB.103.245107","url":null,"abstract":"Since the discovery of the Harper-Hofstadter model, it has been known that condensed matter systems with periodic modulations can be promoted to non-trivial topological states with emergent gauge fields in higher dimensions. In this work, we develop a general procedure to compute the gauge fields in higher dimensions associated to low-dimensional systems with periodic (charge- and spin-) density wave modulations. We construct two-dimensional (2D) models with modulations that can be promoted to higher-order topological phases with $U(1)$ and $SU(2)$ gauge fields in 3D. Corner modes in our 2D models can be pumped by adiabatic sliding of the phase of the modulation, yielding hinge modes in the promoted models. We also examine a 3D Weyl semimetal (WSM) gapped by charge-density wave (CDW) order, possessing quantum anomalous Hall (QAH) surface states. We show that this 3D system is equivalent to a 4D nodal line system gapped by a $U(1)$ gauge field with a nonzero second Chern number. We explain the recently identified interpolation between inversion-symmetry protected phases of the 3D WSM gapped by CDWs using the corresponding 4D theory. Our results can extend the search for (higher-order) topological states in higher dimensions to density wave systems.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85768935","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: 4
Drive dependence of the Hall angle for a sliding Wigner crystal in a magnetic field 磁场中滑动维格纳晶体霍尔角的驱动依赖性
Pub Date : 2020-11-24 DOI: 10.1103/PHYSREVB.103.125107
C. Reichhardt, C. Reichhardt
We numerically examine the depinning and sliding dynamics of a Wigner crystal in the presence of quenched disorder and a magnetic field. In the disorder-free limit, the Wigner crystal Hall angle is independent of crystal velocity, but when disorder is present, we find that Hall angle starts near zero at the depinning threshold and increases linearly with increasing drive before reaching a saturation close to the disorder free value at the highest drives. The drive dependence is the result of a side jump effect produced when the charges move over pinning sites. The magnitude of the side jump is reduced at the higher velocities. The drive dependent Hall angle is robust for a wide range of disorder parameters and should be a generic feature of classical charges driven in the presence of quenched disorder and a magnetic field.
我们用数值方法研究了维格纳晶体在失序淬火和磁场作用下的脱屑和滑动动力学。在无无序极限下,Wigner晶体霍尔角与晶体速度无关,但当无序存在时,我们发现霍尔角在沉降阈值处开始接近于零,随着驱动的增加而线性增加,直到在最高驱动处达到接近无无序值的饱和。驱动依赖是电荷在钉钉位置移动时产生的侧跳效应的结果。在较高的速度下,侧跳的幅度减小。驱动相关的霍尔角在很大范围的无序参数下是鲁棒的,并且应该是在淬火无序和磁场存在下驱动的经典电荷的一般特征。
{"title":"Drive dependence of the Hall angle for a sliding Wigner crystal in a magnetic field","authors":"C. Reichhardt, C. Reichhardt","doi":"10.1103/PHYSREVB.103.125107","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.125107","url":null,"abstract":"We numerically examine the depinning and sliding dynamics of a Wigner crystal in the presence of quenched disorder and a magnetic field. In the disorder-free limit, the Wigner crystal Hall angle is independent of crystal velocity, but when disorder is present, we find that Hall angle starts near zero at the depinning threshold and increases linearly with increasing drive before reaching a saturation close to the disorder free value at the highest drives. The drive dependence is the result of a side jump effect produced when the charges move over pinning sites. The magnitude of the side jump is reduced at the higher velocities. The drive dependent Hall angle is robust for a wide range of disorder parameters and should be a generic feature of classical charges driven in the presence of quenched disorder and a magnetic field.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86731250","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: 4
Revealing defect-induced spin disorder in nanocrystalline Ni 揭示Ni纳米晶中缺陷诱导的自旋紊乱
Pub Date : 2020-11-23 DOI: 10.1103/PHYSREVMATERIALS.5.044409
M. Bersweiler, Evelyn Pratami Sinaga, I. Peral, N. Adachi, P. Bender, N. Steinke, E. Gilbert, Y. Todaka, A. Michels, Y. Oba
We use magnetic small-angle neutron scattering to study the magnetic microstructure of a nanocrystalline Ni bulk sample, which was prepared by straining via high-pressure torsion. The neutron data reveal that the scattering is strongly affected by the high density of crystal defects inside the sample, which were created by the severe plastic deformation during the sample preparation. The defects cause a significant spin-misalignment scattering contribution. The corresponding magnetic correlation length, which characterizes the spatial magnetization fluctuations in real space, indicates an average defect size of 11 nm. In the remanent state, the stray fields around the defects cause spin disorder in the surrounding ferromagnetic bulk, with a penetration depth of around 22 nm. The range and amplitude of the disorder is systematically suppressed by an increasing external magnetic field. Our findings are supported by micromagnetic simulations, which, for the particular case of nonmagnetic defects (holes) embedded in a ferromagnetic Ni phase, further highlight the role of localized spin perturbations for the magnetic microstructure of defect-rich magnets such as high-pressure torsion materials.
利用磁小角中子散射研究了高压扭应变法制备的纳米晶镍体样品的磁性微观结构。中子数据表明,样品内部高密度的晶体缺陷对散射有强烈的影响,这些缺陷是由样品制备过程中剧烈的塑性变形造成的。这些缺陷导致了显著的自旋失调散射贡献。对应的磁相关长度表征了实际空间中的空间磁化波动,表明缺陷的平均尺寸为11 nm。在剩余状态下,缺陷周围的杂散场导致周围铁磁体的自旋无序,穿透深度约为22 nm。紊乱的范围和幅度被一个增大的外磁场系统地抑制。我们的发现得到了微磁模拟的支持,对于嵌入铁磁Ni相的非磁性缺陷(孔)的特殊情况,进一步强调了局部自旋微扰对富含缺陷的磁体(如高压扭转材料)的磁性微观结构的作用。
{"title":"Revealing defect-induced spin disorder in nanocrystalline Ni","authors":"M. Bersweiler, Evelyn Pratami Sinaga, I. Peral, N. Adachi, P. Bender, N. Steinke, E. Gilbert, Y. Todaka, A. Michels, Y. Oba","doi":"10.1103/PHYSREVMATERIALS.5.044409","DOIUrl":"https://doi.org/10.1103/PHYSREVMATERIALS.5.044409","url":null,"abstract":"We use magnetic small-angle neutron scattering to study the magnetic microstructure of a nanocrystalline Ni bulk sample, which was prepared by straining via high-pressure torsion. The neutron data reveal that the scattering is strongly affected by the high density of crystal defects inside the sample, which were created by the severe plastic deformation during the sample preparation. The defects cause a significant spin-misalignment scattering contribution. The corresponding magnetic correlation length, which characterizes the spatial magnetization fluctuations in real space, indicates an average defect size of 11 nm. In the remanent state, the stray fields around the defects cause spin disorder in the surrounding ferromagnetic bulk, with a penetration depth of around 22 nm. The range and amplitude of the disorder is systematically suppressed by an increasing external magnetic field. Our findings are supported by micromagnetic simulations, which, for the particular case of nonmagnetic defects (holes) embedded in a ferromagnetic Ni phase, further highlight the role of localized spin perturbations for the magnetic microstructure of defect-rich magnets such as high-pressure torsion materials.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75796985","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: 6
Double Dirac cones and topologically nontrivial phonons for continuous square symmetric C4(v) and C2(v) unit cells 连续方形对称C4(v)和C2(v)单元格的双狄拉克锥和拓扑非平凡声子
Pub Date : 2020-11-20 DOI: 10.1103/PHYSREVB.103.064308
Yan Lu, Harold S. Park
Because phononic topological insulators have primarily been studied in discrete, graphene-like structures with C$_{6}$ or C$_{3}$ hexagonal symmetry, an open question is how to systematically achieve double Dirac cones and topologically non-trivial structures using continuous, non-hexagonal unit cells. Here, we address this challenge by presenting a novel computational methodology for the inverse design of continuous two-dimensional square phononic metamaterials exhibiting C$_{4v}$ and C$_{2v}$ symmetry. This leads to the systematic design of square unit cell topologies exhibiting a double Dirac degeneracy, which enables topologically-protected interface propagation based on the quantum spin Hall effect (QSHE). Numerical simulations prove that helical edge states emerge at the interface between two topologically distinct square phononic metamaterials, which opens the possibility of QSHE-based pseudospin-dependent transport beyond hexagonal lattices.
由于声子拓扑绝缘体主要是在离散的、具有C$_{6}$或C$_{3}$六边形对称的类石墨烯结构中进行研究,一个悬而未决的问题是如何使用连续的、非六边形单元胞系统地实现双狄拉克锥和拓扑非寻常结构。在这里,我们通过提出一种新的计算方法来解决这一挑战,该方法用于具有C$_{4v}$和C$_{2v}$对称性的连续二维方形声子超材料的反设计。这导致了具有双狄拉克简并的方形单元胞拓扑的系统设计,从而实现了基于量子自旋霍尔效应(QSHE)的拓扑保护界面传播。数值模拟证明,在两种拓扑结构不同的方形声子超材料之间的界面上出现了螺旋边缘态,这开启了基于qshe的假自旋相关输运超越六边形晶格的可能性。
{"title":"Double Dirac cones and topologically nontrivial phonons for continuous square symmetric \u0000C4(v)\u0000 and \u0000C2(v)\u0000 unit cells","authors":"Yan Lu, Harold S. Park","doi":"10.1103/PHYSREVB.103.064308","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.064308","url":null,"abstract":"Because phononic topological insulators have primarily been studied in discrete, graphene-like structures with C$_{6}$ or C$_{3}$ hexagonal symmetry, an open question is how to systematically achieve double Dirac cones and topologically non-trivial structures using continuous, non-hexagonal unit cells. Here, we address this challenge by presenting a novel computational methodology for the inverse design of continuous two-dimensional square phononic metamaterials exhibiting C$_{4v}$ and C$_{2v}$ symmetry. This leads to the systematic design of square unit cell topologies exhibiting a double Dirac degeneracy, which enables topologically-protected interface propagation based on the quantum spin Hall effect (QSHE). Numerical simulations prove that helical edge states emerge at the interface between two topologically distinct square phononic metamaterials, which opens the possibility of QSHE-based pseudospin-dependent transport beyond hexagonal lattices.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80723839","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: 5
Coupling spins to nanomechanical resonators: Toward quantum spin-mechanics 耦合自旋到纳米力学谐振器:走向量子自旋力学
Pub Date : 2020-11-19 DOI: 10.1063/5.0024001
Hailin Wang, I. Lekavicius
Spin-mechanics studies interactions between spin systems and mechanical vibrations in a nanomechanical resonator and explores their potential applications in quantum information processing. In this tutorial, we summarize various types of spin-mechanical resonators and discuss both the cavity-QED-like and the trapped-ion-like spin-mechanical coupling processes. The implementation of these processes using negatively charged nitrogen vacancy and silicon vacancy centers in diamond is reviewed. Prospects for reaching the full quantum regime of spin-mechanics, in which quantum control can occur at the level of both single spin and single phonon, are discussed with an emphasis on the crucial role of strain coupling to the orbital degrees of freedom of the defect centers.
自旋力学研究纳米机械谐振器中自旋系统与机械振动之间的相互作用,并探索其在量子信息处理中的潜在应用。在本教程中,我们总结了各种类型的自旋机械谐振器,并讨论了类腔qed和类阱离子的自旋机械耦合过程。本文综述了利用负电荷氮空位中心和硅空位中心在金刚石中实现这些工艺的方法。讨论了在单自旋和单声子水平上可以实现量子控制的自旋力学的全量子状态的前景,并强调了应变耦合对缺陷中心轨道自由度的关键作用。
{"title":"Coupling spins to nanomechanical resonators: Toward quantum spin-mechanics","authors":"Hailin Wang, I. Lekavicius","doi":"10.1063/5.0024001","DOIUrl":"https://doi.org/10.1063/5.0024001","url":null,"abstract":"Spin-mechanics studies interactions between spin systems and mechanical vibrations in a nanomechanical resonator and explores their potential applications in quantum information processing. In this tutorial, we summarize various types of spin-mechanical resonators and discuss both the cavity-QED-like and the trapped-ion-like spin-mechanical coupling processes. The implementation of these processes using negatively charged nitrogen vacancy and silicon vacancy centers in diamond is reviewed. Prospects for reaching the full quantum regime of spin-mechanics, in which quantum control can occur at the level of both single spin and single phonon, are discussed with an emphasis on the crucial role of strain coupling to the orbital degrees of freedom of the defect centers.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82853859","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: 25
Quantum-limit Hall effect with large carrier density in topological semimetals 拓扑半金属中大载流子密度的量子极限霍尔效应
Pub Date : 2020-11-19 DOI: 10.1103/PhysRevB.103.L241104
Guang Yang, Yi Zhang
The quantum-limit Hall effect at $nu = nh/eBsim O(1)$ that hosts a variety of exotic quantum phenomena requires demanding strong magnetic field $B$ and low carrier density $n$. We propose to realize quantum-limit Hall effect even in the presence of large carrier density residues $n_e$ and $n_h$ relative to the magnetic field $B$ in topological semimetals, where a single Fermi surface contour allow both electron-type and hole-type carriers and approaches charge neutrality as $n_esim n_h$. The underlying filling factor $nu = |n_e-n_h|h/eB$ explicitly violates the Onsager's relation for quantum oscillations.
在$nu = nh/eBsim O(1)$处的量子极限霍尔效应需要强磁场$B$和低载流子密度$n$才能产生各种奇异的量子现象。我们提出即使在拓扑半金属中存在较大载流子密度残馀$n_e$和$n_h$相对于磁场$B$的情况下,也可以实现量子极限霍尔效应,其中单个费米表面等高线允许电子型和空穴型载流子,并接近电荷中性$n_esim n_h$。潜在的填充因子$nu = |n_e-n_h|h/eB$明显违反了量子振荡的Onsager关系。
{"title":"Quantum-limit Hall effect with large carrier density in topological semimetals","authors":"Guang Yang, Yi Zhang","doi":"10.1103/PhysRevB.103.L241104","DOIUrl":"https://doi.org/10.1103/PhysRevB.103.L241104","url":null,"abstract":"The quantum-limit Hall effect at $nu = nh/eBsim O(1)$ that hosts a variety of exotic quantum phenomena requires demanding strong magnetic field $B$ and low carrier density $n$. We propose to realize quantum-limit Hall effect even in the presence of large carrier density residues $n_e$ and $n_h$ relative to the magnetic field $B$ in topological semimetals, where a single Fermi surface contour allow both electron-type and hole-type carriers and approaches charge neutrality as $n_esim n_h$. The underlying filling factor $nu = |n_e-n_h|h/eB$ explicitly violates the Onsager's relation for quantum oscillations.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76371458","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: 1
Advances in dynamic AFM: From nanoscale energy dissipation to material properties in the nanoscale 动态AFM研究进展:从纳米尺度的能量耗散到纳米尺度的材料特性
Pub Date : 2020-11-19 DOI: 10.1063/5.0041366
Sergio Santos, K. Gadelrab, Chia-Yun Lai, Tuza A. Olukan, J. Font, V. Barcons, A. Verdaguer, M. Chiesa
Since the inception of the atomic force microscope AFM, dynamic methods have been very fruitful by establishing methods to quantify dissipative and conservative forces in the nanoscale and by providing a means to apply gentle forces to the samples with high resolution. Here we review developments that cover over a decade of our work on energy dissipation, phase contrast and the extraction of relevant material properties from observables. We describe the attempts to recover material properties via one dimensional amplitude and phase curves from force models and explore the evolution of these methods in terms of force reconstruction, fits of experimental measurements, and the more recent advances in multifrequency AFM.
自从原子力显微镜AFM诞生以来,动态方法通过建立量化纳米尺度上耗散力和保守力的方法,以及提供一种以高分辨率对样品施加温和力的方法,取得了非常富有成效的成果。在这里,我们回顾了十多年来我们在能量耗散、相对比和从可观测物中提取相关材料特性方面的工作进展。我们描述了通过一维振幅和相位曲线从力模型中恢复材料特性的尝试,并探讨了这些方法在力重建、实验测量的拟合以及多频AFM的最新进展方面的演变。
{"title":"Advances in dynamic AFM: From nanoscale energy dissipation to material properties in the nanoscale","authors":"Sergio Santos, K. Gadelrab, Chia-Yun Lai, Tuza A. Olukan, J. Font, V. Barcons, A. Verdaguer, M. Chiesa","doi":"10.1063/5.0041366","DOIUrl":"https://doi.org/10.1063/5.0041366","url":null,"abstract":"Since the inception of the atomic force microscope AFM, dynamic methods have been very fruitful by establishing methods to quantify dissipative and conservative forces in the nanoscale and by providing a means to apply gentle forces to the samples with high resolution. Here we review developments that cover over a decade of our work on energy dissipation, phase contrast and the extraction of relevant material properties from observables. We describe the attempts to recover material properties via one dimensional amplitude and phase curves from force models and explore the evolution of these methods in terms of force reconstruction, fits of experimental measurements, and the more recent advances in multifrequency AFM.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73412635","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: 10
Reduced quantum electrodynamics in curved space 弯曲空间中的简化量子电动力学
Pub Date : 2020-11-18 DOI: 10.1103/PHYSREVD.103.065010
P. Caneda, G. Menezes
The physics of graphene has provided an important connection between quantum field theory and condensed-matter physics due to the particular features of the graphene quasiparticles which can be described as massless two-dimensional Dirac fermions. An approach that has been given promising results in this context is the reduced quantum electrodynamics. In this work we consider the natural generalization of this formalism to curved spaces. As an application, we calculate the one-loop optical conductivity of graphene taking into account the presence of ripples. Such ripples are modeled by curvature effects which can be incorporated by taking into account a suitable chemical potential. In addition, we demonstrate how such effects may contribute to a decisive increase in the minimal conductivity.
石墨烯准粒子具有可描述为二维无质量狄拉克费米子的特性,为量子场论和凝聚态物理之间的联系提供了重要的理论依据。在这种情况下,一种已经给出了有希望的结果的方法是简化量子电动力学。在这项工作中,我们考虑这种形式主义对弯曲空间的自然推广。作为一个应用,我们计算了考虑波纹存在的石墨烯的单环光学导电性。这种波纹是用曲率效应来模拟的,曲率效应可以通过考虑合适的化学势来结合。此外,我们证明了这种效应如何有助于决定性地增加最小电导率。
{"title":"Reduced quantum electrodynamics in curved space","authors":"P. Caneda, G. Menezes","doi":"10.1103/PHYSREVD.103.065010","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.065010","url":null,"abstract":"The physics of graphene has provided an important connection between quantum field theory and condensed-matter physics due to the particular features of the graphene quasiparticles which can be described as massless two-dimensional Dirac fermions. An approach that has been given promising results in this context is the reduced quantum electrodynamics. In this work we consider the natural generalization of this formalism to curved spaces. As an application, we calculate the one-loop optical conductivity of graphene taking into account the presence of ripples. Such ripples are modeled by curvature effects which can be incorporated by taking into account a suitable chemical potential. In addition, we demonstrate how such effects may contribute to a decisive increase in the minimal conductivity.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88082251","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: 1
Electrically induced strong modulation of magnon transport in ultrathin magnetic insulator films 超薄磁绝缘体薄膜中磁振子输运的电诱导强调制
Pub Date : 2020-11-16 DOI: 10.1103/PhysRevB.103.214425
Jian Liu, X. Wei, Gerrit E. W. Bauer, J. Youssef, B. V. Wees
Magnon transport through a magnetic insulator can be controlled by current-biased heavy-metal gates that modulate the magnon conductivity via the magnon density. Here, we report nonlinear modulation effects in 10$,$nm thick yttrium iron garnet (YIG) films. The modulation efficiency is larger than 40%/mA. The spin transport signal at high DC current density (2.2$times 10^{11},$A/m$^{2}$) saturates for a 400$,$nm wide Pt gate, which indicates that even at high current levels a magnetic instability cannot be reached in spite of the high magnetic quality of the films.
磁振子通过磁绝缘体的输运可以通过电流偏置的重金属栅极来控制,通过磁振子密度来调节磁振子的电导率。在这里,我们报道了10$,$nm厚的钇铁石榴石(YIG)薄膜中的非线性调制效应。调制效率大于40% /mA。在高直流电流密度(2.2$乘以10^{11},$A/m$^{2}$)下,400$,$nm宽Pt栅极的自旋输运信号饱和,这表明即使在高电流水平下,尽管薄膜具有高磁性,但也不能达到磁不稳定性。
{"title":"Electrically induced strong modulation of magnon transport in ultrathin magnetic insulator films","authors":"Jian Liu, X. Wei, Gerrit E. W. Bauer, J. Youssef, B. V. Wees","doi":"10.1103/PhysRevB.103.214425","DOIUrl":"https://doi.org/10.1103/PhysRevB.103.214425","url":null,"abstract":"Magnon transport through a magnetic insulator can be controlled by current-biased heavy-metal gates that modulate the magnon conductivity via the magnon density. Here, we report nonlinear modulation effects in 10$,$nm thick yttrium iron garnet (YIG) films. The modulation efficiency is larger than 40%/mA. The spin transport signal at high DC current density (2.2$times 10^{11},$A/m$^{2}$) saturates for a 400$,$nm wide Pt gate, which indicates that even at high current levels a magnetic instability cannot be reached in spite of the high magnetic quality of the films.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75031185","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: 6
期刊
arXiv: Mesoscale and Nanoscale Physics
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1