Condensed Matter最新文献_第3页

Gauge Theories of Josephson Junction Arrays: Why Disorder Is Irrelevant for the Electric Response of Disordered Superconducting Films 约瑟夫森结阵列的规范理论:为什么无序与无序超导薄膜的电响应无关

Condensed Matter Pub Date : 2023-09-19 DOI: 10.3390/condmat8030085

Carlo A. Trugenberger

引用次数: 0

Composed Effects of Electron-Hole Exchange and Near-Field Interaction in Quantum-Dot-Confined Radiative Dipoles 量子点限制辐射偶极子中电子-空穴交换和近场相互作用的复合效应

Condensed Matter Pub Date : 2023-09-16 DOI: 10.3390/condmat8030084

Jaime David Díaz-Ramírez, Shiang-Yu Huang, Bo-Long Cheng, Ping-Yuan Lo, Shun-Jen Cheng, Hanz Yecid Ramírez-Gómez

引用次数: 1

Machine Learning of Nonequilibrium Phase Transition in an Ising Model on Square Lattice 方形晶格上Ising模型非平衡相变的机器学习

Condensed Matter Pub Date : 2023-09-15 DOI: 10.3390/condmat8030083

Dagne Wordofa Tola, Mulugeta Bekele

{"title":"Machine Learning of Nonequilibrium Phase Transition in an Ising Model on Square Lattice","authors":"Dagne Wordofa Tola, Mulugeta Bekele","doi":"10.3390/condmat8030083","DOIUrl":"https://doi.org/10.3390/condmat8030083","url":null,"abstract":"This paper presents the investigation of convolutional neural network (CNN) prediction successfully recognizing the temperature of the nonequilibrium phase transitions in two-dimensional (2D) Ising spins on a square lattice. The model uses image snapshots of ferromagnetic 2D spin configurations as an input shape to provide the average output predictions. By considering supervised machine learning techniques, we perform Metropolis Monte Carlo (MC) simulations to generate the configurations. In the equilibrium Ising model, the Metropolis algorithm respects detailed balance condition (DBC), while its nonequilibrium version violates DBC. Violating the DBC of the algorithm is characterized by a parameter −8<ε<8. We find the exact result of the transition temperature Tc(ε) in terms of ε. If we set ε=0, the usual single spin-flip algorithm can be restored, and the equilibrium configurations generated with such a set up are used to train our model. For ε≠0, the system attains the nonequilibrium steady states (NESS), and the modified algorithm generates NESS configurations (test dataset). The trained model is successfully tested on the test dataset. Our result shows that CNN can determine Tc(ε≠0) for various ε values, consistent with the exact result.","PeriodicalId":10665,"journal":{"name":"Condensed Matter","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135437818","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

Elliptical Quantum Rings with Variable Heights and under Spin–Orbit Interactions 自旋轨道相互作用下的变高度椭圆量子环

Condensed Matter Pub Date : 2023-09-11 DOI: 10.3390/condmat8030082

Miguel E. Mora-Ramos, Juan A. Vinasco, A. Radu, Ricardo L. Restrepo, Alvaro L. Morales, Mehmet Sahin, Omar Mommadi, José Sierra-Ortega, Gene Elizabeth Escorcia-Salas, Carlos A. Duque

{"title":"Elliptical Quantum Rings with Variable Heights and under Spin–Orbit Interactions","authors":"Miguel E. Mora-Ramos, Juan A. Vinasco, A. Radu, Ricardo L. Restrepo, Alvaro L. Morales, Mehmet Sahin, Omar Mommadi, José Sierra-Ortega, Gene Elizabeth Escorcia-Salas, Carlos A. Duque","doi":"10.3390/condmat8030082","DOIUrl":"https://doi.org/10.3390/condmat8030082","url":null,"abstract":"We investigate the electronic properties of a semiconductor quantum ring with an elliptical shape and non-uniform height, allowing for distributed quantum-dot-like bulges along its perimeter. The adiabatic approximation and the finite element method are combined to calculate the allowed electron states in the structure under the effective mass approximation, considering the contributions from Rashba and Dresselahaus spin–orbit interactions and the Zeeman effect in the presence of an applied magnetic field. We discuss the features of the calculated spectra for two different ring geometries: a symmetric one with four dot-like bulges, and an asymmetric one with three hilled protuberances. The information about those states allows us to evaluate the linear optical absorption response associated with interlevel transitions between the ground and lowest excited states. This phenomenon takes place at resonant energies of only a few milielectronvolts. It is observed that spin–orbit interactions tend to quench this response under zero-field conditions in the case of symmetric confinement.","PeriodicalId":10665,"journal":{"name":"Condensed Matter","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135981301","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 DFT + U Study on the Stability of Small CuN Clusters (N = 3–6 Atoms): Calculation of Phonon Frequencies N = 3-6个原子的CuN簇稳定性的DFT + U研究:声子频率的计算

Condensed Matter Pub Date : 2023-09-11 DOI: 10.3390/condmat8030081

Luis A. Alcalá-Varilla, Rafael E. Ponnefz-Durango, Nicola Seriani, Eduard Araujo-Lopez, Javier A. Montoya

{"title":"A DFT + U Study on the Stability of Small CuN Clusters (N = 3–6 Atoms): Calculation of Phonon Frequencies","authors":"Luis A. Alcalá-Varilla, Rafael E. Ponnefz-Durango, Nicola Seriani, Eduard Araujo-Lopez, Javier A. Montoya","doi":"10.3390/condmat8030081","DOIUrl":"https://doi.org/10.3390/condmat8030081","url":null,"abstract":"Despite the interest in copper clusters, a consensus on their atomic structure is still lacking. The experimental observation of isolated clusters is difficult, and theoretical predictions vary widely. The latter is because one must adequately describe the closed shell of d electrons both in its short- and long-range effects. Herein, we investigate the stability of small copper clusters (CuN, N = 3–6 atoms) using spin-polarized DFT calculations under the GGA approximation, the Hubbard U correction, and the van der Waals forces. We found that the spin-polarized and vdW contributions have little effect on the binding energies of the isomers. The inclusion of U represents the most relevant contribution to the ordering of the CuN isomers, and our calculated binding energies for the clusters agreed with the experimental values. We also found that atomic relaxations alone are not enough to determine the stability of small copper clusters. It is also necessary to build the energy landscape or calculate the vibrational frequencies of the isomers. We found that the vibrational frequencies of the isomers were in the THz range and the normal modes of vibration were discrete. This approach is relevant to future studies involving isolated or supported copper clusters.","PeriodicalId":10665,"journal":{"name":"Condensed Matter","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135979417","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

Double Quantum Ring under an Intense Nonresonant Laser Field: Zeeman and Spin-Orbit Interaction Effects 强非共振激光场下的双量子环:塞曼和自旋轨道相互作用效应

Condensed Matter Pub Date : 2023-09-08 DOI: 10.3390/condmat8030079

Miguel E. Mora-Ramos, Juan A. Vinasco, Adrian Radu, Ricardo L. Restrepo, Alvaro L. Morales, Mehmet Sahin, Omar Mommadi, José Sierra-Ortega, Gene Elizabeth Escorcia-Salas, Christian Heyn, Derfrey A. Duque, Carlos A. Duque

引用次数: 0

Two-Dimensional Discommensurations: An Extension to McMillan’s Ginzburg–Landau Theory 二维反相：麦克米兰金兹堡-朗道理论的扩展

IF 1.7

Condensed Matter Pub Date : 2023-09-08 DOI: 10.3390/condmat8040100

L. Mertens, Jeroen van den Brink, J. V. Wezel

{"title":"Two-Dimensional Discommensurations: An Extension to McMillan’s Ginzburg–Landau Theory","authors":"L. Mertens, Jeroen van den Brink, J. V. Wezel","doi":"10.3390/condmat8040100","DOIUrl":"https://doi.org/10.3390/condmat8040100","url":null,"abstract":"Charge density waves (CDWs) profoundly affect the electronic properties of materials and have an intricate interplay with other collective states, like superconductivity and magnetism. The well-known macroscopic Ginzburg–Landau theory stands out as a theoretical method for describing CDW phenomenology without requiring a microscopic description. In particular, it has been instrumental in understanding the emergence of domain structures in several CDW compounds, as well as the influence of critical fluctuations and the evolution towards or across lock-in transitions. In this context, McMillan’s foundational work introduced discommensurations as the objects mediating the transition from commensurate to incommensurate CDWs, through an intermediate nearly commensurate phase characterised by an ordered array of phase slips. Here, we extended the simplified, effectively one-dimensional, setting of the original model to a fully two-dimensional analysis. We found exact and numerical solutions for several types of discommensuration patterns and provide a framework for consistently describing multi-component CDWs embedded in quasi-two-dimensional atomic lattices.","PeriodicalId":10665,"journal":{"name":"Condensed Matter","volume":"57 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139341657","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

Prospects of Using Fe-Ga Alloys for Magnetostrictive Applications at High Frequencies Fe-Ga合金在高频磁致伸缩中的应用前景

Condensed Matter Pub Date : 2023-09-08 DOI: 10.3390/condmat8030080

Vasily Milyutin, Radovan Bureš, Maria Fáberová

引用次数: 0

The Superconducting Dome in Artificial High-Tc Superlattices Tuned at the Fano–Feshbach Resonance by Quantum Design 用量子设计在Fano–Feshbach共振下调谐的人造高Tc超晶格中的超导圆顶

IF 1.7

Condensed Matter Pub Date : 2023-09-06 DOI: 10.3390/condmat8030078

G. Logvenov, Nicolas Bonmassar, G. Christiani, G. Campi, A. Valletta, Antonio Bianconi

{"title":"The Superconducting Dome in Artificial High-Tc Superlattices Tuned at the Fano–Feshbach Resonance by Quantum Design","authors":"G. Logvenov, Nicolas Bonmassar, G. Christiani, G. Campi, A. Valletta, Antonio Bianconi","doi":"10.3390/condmat8030078","DOIUrl":"https://doi.org/10.3390/condmat8030078","url":null,"abstract":"While the search for new high-temperature superconductors had been driven by the empirical “trials and errors” method for decades, we now report the synthesis of Artificial High-Tc Superlattices (AHTS) designed by quantum mechanics theory at the nanoscale. This discovery paves the way for engineering a new class of high-temperature superconductors, following the predictions of the Bianconi Perali Valletta (BPV) theory recently implemented in 2022 by Mazziotti et al. including Rashba spin-orbit coupling to create nanoscale AHTS composed of quantum wells. The high-Tc superconducting properties within these superlattices are controlled by a conformational parameter of the superlattice geometry, specifically, the ratio L/d which represents the thickness of La2CuO4 layers (L) relative to the superlattice period (d). Using molecular beam epitaxy, we have successfully grown numerous AHTS samples. These samples consist of initial layers of stoichiometric La2CuO4 units with a thickness L, doped by interface space charge, and intercalated with second layers of non-superconducting metallic material, La1.55Sr0.45CuO4 with thickness denoted as W = d − L. This configuration forms a quantum superlattice with periodicity d. The agreement observed between the experimental dependence Tc (the superconducting transition temperature) versus L/d ratio and the predictions of the BPV theory for AHTS in the form of the superconducting dome validates the hypothesis that the superconducting dome arises from the Fano–Feshbach or shape resonance in multigap superconductivity driven by quantum nanoscale confinement.","PeriodicalId":10665,"journal":{"name":"Condensed Matter","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45373592","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

Ab Initio Study of Structural, Electronic, and Thermal Properties of Pt/Pd-Based Alloys Pt/ pd基合金的结构、电子和热性能从头算研究

IF 1.7

Condensed Matter Pub Date : 2023-09-05 DOI: 10.3390/condmat8030076

L. Botha, Cecil Naphtaly Moro Ouma, K. Obodo, D. Bessarabov, Denis Lvovich Sharypin, Pyotr Sergeevich Varyushin, Elizaveta Ivanovna Plastinina

{"title":"Ab Initio Study of Structural, Electronic, and Thermal Properties of Pt/Pd-Based Alloys","authors":"L. Botha, Cecil Naphtaly Moro Ouma, K. Obodo, D. Bessarabov, Denis Lvovich Sharypin, Pyotr Sergeevich Varyushin, Elizaveta Ivanovna Plastinina","doi":"10.3390/condmat8030076","DOIUrl":"https://doi.org/10.3390/condmat8030076","url":null,"abstract":"Alloys are beneficial in numerous applications since they combine the desirable properties of different metals. In this regard, Pt/Pd alloys have been investigated as a replacement for Pt, which is the standard catalyst used in various catalytic processes. However, there are still gaps in our understanding of the structural, mechanical, and thermodynamic properties of Pt/Pd alloys. This study was conducted using density functional theory (DFT) calculations to investigate the electronic, elasticity, mechanical, and thermodynamic properties of Pt/Pd alloys and compared them to pristine Pt and Pd structures. The results indicate that the considered Pt/Pd alloy structures, PtPd3, PtPd, Pt3Pd, and Pt7Pd, are energetically favourable based on their formation energies. These structures also satisfy Born’s stability criteria and are elastically stable. The phonon density of states showed that the considered Pt/Pd alloy structures are dynamically stable, with no imaginary modes present. Additionally, the Pt atom dominates at lower frequencies, while the Pd atom dominates at higher frequencies, as seen in the phonon band structure. The electronic density of states revealed that the considered Pt/Pd alloy structures have a metallic character and are non-magnetic. These findings contribute to a better understanding of the properties and stability of Pt/Pd alloy structures that are relevant in various fields, including materials science and catalysis.","PeriodicalId":10665,"journal":{"name":"Condensed Matter","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42714127","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