Journal of Physics: Condensed Matter最新文献_第9页

Threshold temperature of superfluorescence generation in CuCl quantum dots under resonant excitation of excitons and resonant two-photon excitation of biexcitons. 在共振激发激子和共振双光子激发双光子的情况下，CuCl 量子点中超荧光产生的阈值温度。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-08-01 DOI: 10.1088/1361-648X/ad636c

Kohei Kawamura, Tomoharu Yoshida, Jun Ishihara, Akira Ishikawa, Kensuke Miyajima

{"title":"Threshold temperature of superfluorescence generation in CuCl quantum dots under resonant excitation of excitons and resonant two-photon excitation of biexcitons.","authors":"Kohei Kawamura, Tomoharu Yoshida, Jun Ishihara, Akira Ishikawa, Kensuke Miyajima","doi":"10.1088/1361-648X/ad636c","DOIUrl":"10.1088/1361-648X/ad636c","url":null,"abstract":"We studied the threshold temperature of superfluorescence (SF) generation with regard to biexcitons in CuCl quantum dots (QDs) under resonant two-photon excitation of biexcitons and resonant excitation of excitons to demonstrate the influence of initial population densities in the QDs on SF generation. As a result, the threshold temperature under the resonant excitation of excitons was higher than that under the two-photon excitation of biexcitons. This indicates that the high density of excited dots facilitates the rapid establishment of coherence among the dots, overcoming disadvantages of incomplete population inversion and formation process of biexcitons. We performed a theoretical calculation of the time profiles of the biexcitonic emission based on semiconductor luminescence equations. The experimentally obtained temperature dependence of the time profiles was qualitatively reproduced by calculating their dependence on the dephasing rate. In addition, we estimated the temperature dependence of the phase relaxation time of the biexcitons in the CuCl QDs by analyzing the temperature dependence of SF.","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141620228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Field theoretic description of nonlinear electro-optical responses in centrosymmetric electronic systems. 中心对称电子系统中非线性电光响应的场论描述。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-08-01 DOI: 10.1088/1361-648X/ad65ac

I Paul

{"title":"Field theoretic description of nonlinear electro-optical responses in centrosymmetric electronic systems.","authors":"I Paul","doi":"10.1088/1361-648X/ad65ac","DOIUrl":"10.1088/1361-648X/ad65ac","url":null,"abstract":"Motivated by the recent developments in terahertz spectroscopy using pump-probe setups to study correlated electronic materials, we review the field theoretical formalism to compute finite frequency nonlinear electro-optical responses in centrosymmetric systems starting from basic time dependent perturbation theory. We express the nonlinear current kernel as a sum of several causal response functions. These causal functions cannot be evaluated using perturbative field theory methods, since they are not contour ordered. Consequently, we associate each response function with a corresponding imaginary time ordered current correlation function, since the latter can be factorized using Wick's theorem. The mapping between the response functions and the correlation functions, suitably analytically continued to real frequencies, is proven exactly. We derive constraints satisfied by the nonlinear current kernel and we prove a generalizedf-sum rule for the nonlinear conductivity, all of which are consequences of particle number conservation. The constraints guarantee that the nonlinear static responses are free from spurious divergences. We apply the theory to compute the gauge invariant nonlinear conductivity of a system of noninteracting electrons in the presence of weak disorder. As special cases of this generalized nonlinear response, we discuss its third harmonic and its instantaneous terahertz Kerr signals. The formalism can be used to compute the nonlinear conductivity in symmetry broken phases of electronic systems such as superconductors, density waves and nematic states.","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141727356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Predicting surface-energy anisotropy of metals with geometric properties of surfaces and atoms. 用表面和原子的几何特性预测金属的表面能量各向异性

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-07-31 DOI: 10.1088/1361-648X/ad665d

Xin Li, Hao Wu, Wang Gao

引用次数: 0

Special Issue on Solitons in Quantum Physics. 特刊前言。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-07-30 DOI: 10.1088/1361-648X/ad5d3e

Suk Bum Chung, Se Kwon Kim, Egor Babaev, Jiadong Zang

引用次数: 0

Strain-dependence of Te interstitial diffusion in CdTe. 碲化镉中碲间二溶的应变依赖性。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-07-30 DOI: 10.1088/1361-648X/ad61ac

Sameer Hamadna, Jacques G Amar

{"title":"Strain-dependence of Te interstitial diffusion in CdTe.","authors":"Sameer Hamadna, Jacques G Amar","doi":"10.1088/1361-648X/ad61ac","DOIUrl":"10.1088/1361-648X/ad61ac","url":null,"abstract":"While the dominant defects which control non-radiative recombination and long-range interstitial diffusion in CdTe correspond to Cd vacancies and Te anti-sites, the short-range diffusion of Te and Se interstitials between these defects is also of interest, since they both play a role in defect passivation. In addition, since CdTe thin films are typically polycrystalline and may also involve interfaces with materials with different lattice constants, the effects of strain are also of interest. Here we present the results of molecular dynamics (MD) simulations of Te interstitial diffusion in zincblende CdTe for values of the triaxial strain ranging from -2% (compressive) strain to +2.8% (tensile) strain. By carrying out MD simulations of Te interstitial diffusion over a range of temperatures, and then carrying out Arrhenius fits, we have determined the effective activation barrierEaand prefactorD0for each value of the global strain. We find that bothEaandD0exhibit non-monotonic behavior, increasing with both compressive and tensile strain. We also present an analysis of the key diffusion pathways for 3 different values of the strain which explains the non-monotonic strain dependence obtained in our simulations. Our results also indicate that in each case, the diffusion of interstitial Te involves a variety of concerted events with a wide range of activation barriers.","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141580041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Magnetic skin effect in Pb(Fe _{1/2}$Nb _{1/2}$)O₃. Pb(Fe1/2Nb1/2)O3 中的磁集肤效应。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-07-29 DOI: 10.1088/1361-648X/ad6523

N Giles-Donovan, A D Hillier, K Ishida, B V Hampshire, S R Giblin, B Roessli, P M Gehring, G Xu, X Li, H Luo, S Cochran, C Stock

{"title":"Magnetic skin effect in Pb(Fe _{1/2}$Nb _{1/2}$)O3.","authors":"N Giles-Donovan, A D Hillier, K Ishida, B V Hampshire, S R Giblin, B Roessli, P M Gehring, G Xu, X Li, H Luo, S Cochran, C Stock","doi":"10.1088/1361-648X/ad6523","DOIUrl":"10.1088/1361-648X/ad6523","url":null,"abstract":"Relaxor-ferroelectrics display exceptional dielectric properties resulting from the underlying random dipolar fields induced by strong chemical inhomogeneity. An unusual structural aspect of relaxors is a skin-effect where the near-surface region in single crystals exhibit structures and critical phenomena that differ from the bulk. Relaxors are unique in that this skin effect extends over a macroscopic lengthscale of ∼100 μmwhereas usual surface layers only extend over a few unit cells (or ∼nm). We present a muon spectroscopy study of Pb(Fe_{1/2}Nb_{1/2})O3(PFN) which displays ferroelectric order, including many relaxor-like dielectric properties such as a frequency broadened dielectric response, and antiferromagnetism with spatially short-range polar correlations and hence can be termed a multiferroic. In terms of the magnetic behavior determined by the Fe3+(S=5/2,L ≈ 0) ions, PFN has been characterized as a unique example of a 'cluster spin-glass'. We use variable momentum muon spectroscopy to study the depth dependence of the slow magnetic relaxations in a large 1 cm3crystal of PFN. Zero-fieldpositivemuon spin relaxation is parameterized using a stretched exponential, indicative of a distribution of relaxation rates of the Fe3+spins. This bandwidth of frequencies changes as a function of muon momentum, indicative of a change in the Fe3+relaxation rates as a function of muon implantation depth in our single crystal. Usingnegativemuon elemental analysis, we find small-to-no measurable change in the Fe3+/Nb5+concentration with depth implying that chemical concentration alone cannot account for the change in the relaxational dynamics. PFN displays an analogous magnetic skin effect reported to exist in the structural properties of relaxor-ferroelectrics.","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141723759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Chemical pressure induced spin reorientation in the magnetic structure ofCa3Mn2-xSnxO7(x=0,0.03,0.05). 化学压力诱导 Ca3Mn2-xSnxO7（x = 0.03，0.05）磁性结构中的自旋重新定向。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-07-26 DOI: 10.1088/1361-648X/ad636d

Ashwin Mohan, Salil S Vaidya, Anil Jain, S M Yusuf

{"title":"Chemical pressure induced spin reorientation in the magnetic structure ofCa3Mn2-xSnxO7(x=0,0.03,0.05).","authors":"Ashwin Mohan, Salil S Vaidya, Anil Jain, S M Yusuf","doi":"10.1088/1361-648X/ad636d","DOIUrl":"10.1088/1361-648X/ad636d","url":null,"abstract":"The effect of partially substituting Tin (Sn) at the Manganese (Mn) site ofCa3Mn2O7, viz.Ca3Mn2-xSnxO7withx=0.03,0.05, on its structural and magnetic properties have been investigated using synchrotron diffraction, neutron diffraction, and bulk magnetization measurements. It is observed that with a substitution ofx=0.03, the minor (≈8%) tetragonal (I4/mmm) structural phase that is present in the predominantly orthorhombic (Cmc21) undopedCa3Mn2O7, completely disappears. The compounds order antiferromagnetically, the ordering temperature decreases with increasing Sn-content, indicating a weakening of the antiferromagnetic exchange interactions. Interestingly, in the ordered state, the spin magnetic moments which were aligned along thea-axis of the unit cell in the undoped compound, are observed to have reoriented with their major components lying in theb - cplane in the Sn-doped compounds. The above influence of Sn-doping is seen to be stemming from a significant modification of the octahedral rotation and tilt mode geometry in the unit cell, that is known to be responsible for driving ferroelectricity in these compounds.","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141620226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Advancements and challenges in strained group-IV-based optoelectronic materials stressed by ion beam treatment. 基于离子束处理的应变 IV 族光电材料的进展与挑战。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-07-26 DOI: 10.1088/1361-648X/ad649f

Mateus G Masteghin, Benedict N Murdin, Dominic A Duffy, Steven K Clowes, David C Cox, Stephen J Sweeney, Roger P Webb

引用次数: 0

Integrating machine learning and the finite element method for assessing stiffness degradation in photovoltaic modules. 整合机器学习和有限元法，评估光伏组件的刚度退化。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-07-26 DOI: 10.1088/1361-648X/ad64a1

Weiqing Li

{"title":"Integrating machine learning and the finite element method for assessing stiffness degradation in photovoltaic modules.","authors":"Weiqing Li","doi":"10.1088/1361-648X/ad64a1","DOIUrl":"10.1088/1361-648X/ad64a1","url":null,"abstract":"This study introduces a novel machine learning (ML) method utilizing a stacked auto-encoder network to predict stiffness degradation in photovoltaic (PV) modules with pre-existing cracks. The input data for the training process was derived from numerical simulations, ensuring a comprehensive representation of module behavior under various conditions. The findings highlight the robust predictive capability of the model, as evidenced by its impressive R2value of 0.961 and notably low root mean square error (RMSE) of 4.02%. These metrics significantly outperform those of other conventional methods, including the artificial neural network with R2of 0.905 and RMSE of 9.43%, the space vector machine with R2of 0.827 and RMSE of 17.93%, and the random forest (RF) with R2of 0.899 and RMSE of 11.02%. Moreover, the findings suggest that the predictive dynamics of degradation are affected by the varying weight functions of different input parameters, such as climate temperature (CT), grain size (GS), material effort, and pre-crack size, as the degradation level changes. Furthermore, a geometric analysis reveals model deficiencies where significant overestimations correlate with thicker glass components, while pronounced underestimations are predominantly associated with thinner layers of polycrystalline silicon wafer and Ethylene Vinyl Acetate in the module. As a case study, it demonstrated that to maintain a constant degradation level between 1.30 and 1.32 in a PV module with components featuring consistent geometric attributes, the input parameters must be kept within specific ranges: CT ranging from 33 °C to 57 °C, GS ranging from 36 to 81μm, material effort ranging from 0.74 to 0.81, and pre-crack size ranging from 24 to 32μm. Therefore, this underscores that the ML model not only predicts degradation but also delineates the parameter space required to achieve a consistent output value.","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141633831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Rare-earth (Eu³⁺) substitution impact on the structural, morphological, magneto-dielectric, and electrochemical properties of Cd_0.45Co_0.55Fe_2-yEu_yO₄spinel nanoferrites. 稀土（Eu3+）替代对〖镉〗_(0.45) 〖钴〗_(0.55) 〖铁〗_(2-y) 〖欧〗_y O_(4)尖晶石纳米铁氧体的结构、形貌、磁介质和电化学性能的影响。

IF 2.3 4区物理与天体物理

Journal of Physics: Condensed Matter Pub Date : 2024-07-25 DOI: 10.1088/1361-648X/ad62d0

F Afzal, A Alhadhrami, Mohamed M Ibrahim, Zeinhom M El-Bahy, A U Rahman

{"title":"Rare-earth (Eu3+) substitution impact on the structural, morphological, magneto-dielectric, and electrochemical properties of Cd0.45Co0.55Fe2-yEuyO4spinel nanoferrites.","authors":"F Afzal, A Alhadhrami, Mohamed M Ibrahim, Zeinhom M El-Bahy, A U Rahman","doi":"10.1088/1361-648X/ad62d0","DOIUrl":"10.1088/1361-648X/ad62d0","url":null,"abstract":"A series ofCd0.45Co0.55Fe2-yEuyO4(y= 0.0, 0.1, 0.2, 0.3) spinel nanoferrites (SNFs) were synthesized using a self-igniting process and employed as electrode materials for supercapacitor applications. The results demonstrated the formation of a single SNFs phase, as shown by the XRD data. The crystallite size lies between the range of 29.30-51.12 nm. The porosity percentage is within the range of 31.37%-32.99%. Rietveld refinement of XRD and Raman analysis revealed the pure spinel phase and no secondary phase was observed. The saturation magnetization and magnetic anisotropy were also decreased with the addition of Eu3+in Cd-Co SNFs. The high coercive field was enhanced for Eu3+doping as compared to pure Cd-Co SNFs. The dielectric constant was improved with the substitution of Eu3+in Cd-Co SNFs. The dielectric tangent loss was reduced with the doping of Eu3+. The electrochemical performance of the Eu3+doped Cd-Co SNFs achieved an impressive maximum specific capacitance at a lower scan rate. Based on these findings, the outstanding electrochemical performance of the Eu3+doped Cd-Co SNFs suggests their potential as promising materials for high-frequency, magnetic ferrofluid, and supercapacitor electrodes.","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141600265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0