arXiv: Mesoscale and Nanoscale Physics最新文献_第7页

Controlling the direction of topological transport in a non-Hermitian time-reversal symmetric Floquet ladder 控制非厄米时间反转对称Floquet梯的拓扑输运方向

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-16 DOI: 10.1063/5.0036494

Bastian Hockendorf, A. Alvermann, H. Fehske

引用次数: 2

Emergence of strain-induced moiré patterns and pseudomagnetic field confined states in graphene 石墨烯中应变诱导的莫尔条纹和伪磁场约束态的出现

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-16 DOI: 10.1103/physrevb.102.235410

Md. Tareq Mahmud, N. Sandler

{"title":"Emergence of strain-induced moiré patterns and pseudomagnetic field confined states in graphene","authors":"Md. Tareq Mahmud, N. Sandler","doi":"10.1103/physrevb.102.235410","DOIUrl":"https://doi.org/10.1103/physrevb.102.235410","url":null,"abstract":"Strain-inducing deformations in graphene alter charge distributions and provide a new method to design specific features in the band structure and transport properties. Novel approaches implement engineered substrates to induce specifically targeted strain profiles. Motivated by this technique, we study the evolution of charge distributions with an increasing number of out-of-plane deformations as an example of a finite size periodic substrate. We first analyze a system of two overlapping deformations and determine the quantitative relation between geometrical parameters and features in the local density of states. We extend the study to sets of 3 and 4 deformations in linear and two-dimensional arrays and observe the emergence of moire patterns that are more pronounced for a hexagonal cell composed of 7 deformations. A comparison between the induced strain profile and spatial maps of the local density of states at different energies provides evidence for the existence of states confined by the pseudo-magnetic field in bounded regions, reminiscent of quantum dots structures. Due to the presence of these states, the energy level scaling to be observed by local probes should exhibit a linear dependence with the pseudo-field, in contrast to the expected scaling of pseudo-Landau levels.","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":"73285920","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

First-principles based analysis of thermal transport in metallic nanostructures: Size effect and Wiedemann-Franz law 基于第一性原理的金属纳米结构热输运分析:尺寸效应和Wiedemann-Franz定律

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-16 DOI: 10.1103/PHYSREVB.103.104301

Yue Hu, Shouhang Li, Hua Bao

{"title":"First-principles based analysis of thermal transport in metallic nanostructures: Size effect and Wiedemann-Franz law","authors":"Yue Hu, Shouhang Li, Hua Bao","doi":"10.1103/PHYSREVB.103.104301","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.104301","url":null,"abstract":"Metallic nanostructures (the nanofilms and nanowires) are widely used in electronic devices, and their thermal transport properties are crucial for heat dissipation. However, there are still gaps in understanding thermal transport in metallic nanostructures, especially regarding the size effect and validity of the Wiedemann-Franz law. In this work, we perform mode-by-mode first-principles calculations combining the Boltzmann transport equation to understand thermal transport in metallic nanostructures. We take the gold (Au) and tungsten (W) nanostructures as prototypes. It is found that when the size of nanostructures is on the order of several tens of nanometers, the electronic/phonon thermal conductivity is smaller than the bulk value and decreases with size. The phonon contribution increases in nanostructures for those metals with small bulk phonon thermal conductivity (like Au), while the phonon contribution may increase or be suppressed in nanostructures for those metals with large bulk phonon thermal conductivity (like W). By assuming that the grain boundary does not induce inelastic electron-phonon scattering, the Wiedemann-Franz law works well in both Au and W nanostructures if the Lorentz ratio is estimated using electronic thermal conductivity. The Wiedemann-Franz law also works well in Au nanostructures when the Lorentz ratio is estimated by total thermal conductivity.","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":"72619291","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

Magnetic anisotropy of individual maghemite mesocrystals 磁铁矿各介晶的磁各向异性

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-13 DOI: 10.1103/physrevb.103.014402

B. Gross, S. Philipp, E. Josten, J. Leliaert, E. Wetterskog, L. Bergström, M. Poggio

{"title":"Magnetic anisotropy of individual maghemite mesocrystals","authors":"B. Gross, S. Philipp, E. Josten, J. Leliaert, E. Wetterskog, L. Bergström, M. Poggio","doi":"10.1103/physrevb.103.014402","DOIUrl":"https://doi.org/10.1103/physrevb.103.014402","url":null,"abstract":"Interest in creating magnetic metamaterials has led to methods for growing superstructures of magnetic nanoparticles. Mesoscopic crystals of maghemite ($gammatext{-Fe}_2text{O}_3$) nanoparticles can be arranged into highly ordered body-centered tetragonal lattices of up to a few micrometers. Although measurements on disordered ensembles have been carried out, determining the magnetic properties of individual mesoscopic crystals is challenging due to their small total magnetic moment. Here, we overcome these challenges by utilizing sensitive dynamic cantilever magnetometry to study individual micrometer-sized $gammatext{-Fe}_2text{O}_3$ mesocrystals. These measurements reveal an unambiguous cubic anisotropy, resulting from the crystalline anisotropy of the constituent maghemite nanoparticles and their alignment within the mesoscopic lattice. The signatures of anisotropy and its orgins come to light because we combine the self-assembly of highly ordered mesocrystals with the ability to resolve their individual magnetism. This combination is promising for future studies of the magnetic anisotropy of other nanoparticles, which are too small to investigate individually.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73077276","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

Interface-enhanced helicity dependent photocurrent in metal/semimetal bilayers 金属/半金属双分子层中界面增强的螺旋度相关光电流

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-13 DOI: 10.1103/PhysRevB.103.174437

H. Hirose, M. Kawaguchi, Y. Lau, Z. Chi, F. Freimuth, K. Takanashi, M. Hayashi

引用次数: 3

Profilometry and stress analysis of suspended nanostructured thin films 悬浮纳米结构薄膜的轮廓学和应力分析

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-13 DOI: 10.1063/5.0037406

A. A. Darki, Alexios Parthenopoulos, J. Nygaard, A. Dantan

引用次数: 6

Nonlinear Charge- and Flux-Tunable Cavity Derived From an Embedded Cooper-Pair Transistor 基于嵌入式铜对晶体管的非线性电荷和磁通可调谐腔

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-12 DOI: 10.1103/PHYSREVAPPLIED.15.044009

B. L. Brock, Juliang Li, S. Kanhirathingal, B. Thyagarajan, W. Braasch, Miles Blencowe, A. Rimberg

引用次数: 8

Bloch–Landau–Zener dynamics induced by a synthetic field in a photonic quantum walk 光子量子行走中合成场诱导的布洛赫-朗多-齐纳动力学

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-11 DOI: 10.1063/5.0037327

A. D’Errico, R. Barboza, R. Tudor, A. Dauphin, P. Massignan, L. Marrucci, F. Cardano

引用次数: 11

Voltage-Tunable Quantum-Dot Array by Patterned Ge-Nanowire-Based Metal-Oxide-Semiconductor Devices 基于图形化纳米线的金属氧化物半导体器件的电压可调量子点阵列

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-11 DOI: 10.1103/PhysRevApplied.15.054060

Subhrajit Sikdar, B. N. Chowdhury, R. Saha, S. Chattopadhyay

{"title":"Voltage-Tunable Quantum-Dot Array by Patterned \u0000Ge\u0000-Nanowire-Based Metal-Oxide-Semiconductor Devices","authors":"Subhrajit Sikdar, B. N. Chowdhury, R. Saha, S. Chattopadhyay","doi":"10.1103/PhysRevApplied.15.054060","DOIUrl":"https://doi.org/10.1103/PhysRevApplied.15.054060","url":null,"abstract":"Semiconductor quantum dots (QDs) are being regarded as the primary unit for a wide range of advanced and emerging technologies including electronics, optoelectronics, photovoltaics and biosensing applications as well as the domain of q-bits based quantum information processing. Such QDs are suitable for several novel device applications for their unique property of confining carriers 3-dimensionally creating discrete quantum states. However, the realization of such QDs in practice exhibits serious challenge regarding their fabrication in array with desired scalability and repeatability as well as control over the quantum states at room temperature. In this context, the current work reports the fabrication of an array of highly scaled Ge-nanowire (radius ~25 nm) based vertical metal-oxide-semiconductor devices that can operate as voltage tunable quantum dots at room temperature. The electrons in such nanowire experience a geometrical confinement in the radial direction, whereas, they can be confined axially by tuning the applied bias in order to manipulate the quantum states. Such quantum confinement of electrons has been confirmed from the step-like responses in the room temperature capacitance-voltage (C-V) characteristics at relatively low frequency (200 kHz). Each of such steps has observed to encompass convolution of the quantized states occupying ~6 electronic charges. The details of such carrier confinement are analyzed in the current work by theoretically modeling the device transport properties based on non-equilibrium Green's function (NEGF) formalism.","PeriodicalId":8465,"journal":{"name":"arXiv: Mesoscale and Nanoscale Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74073614","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: 7

Polariton spin jets through optical control 通过光学控制的极化子自旋射流

arXiv: Mesoscale and Nanoscale Physics Pub Date : 2020-11-11 DOI: 10.1103/PHYSREVB.103.155302

L. Pickup, J. Töpfer, H. Sigurdsson, P. Lagoudakis

引用次数: 5