{"title":"THz optical response of Ba(Fe1−xNix)2As2 films analyzed within the three-band Eliashberg s±-wave model","authors":"","doi":"10.1016/j.jpcs.2024.112364","DOIUrl":null,"url":null,"abstract":"<div><div>The uncertainty of the nature of the normal state and superconducting condensate of unconventional superconductors continues to stimulate considerable speculation about the mechanism of superconductivity in these materials. Of particular interest are the type of symmetry of the order parameter and the basic electronic characteristics of the superconducting and normal states. We report the derivation of temperature dependences of the superconducting condensate plasma frequency, superfluid density, and London penetration depth by measuring terahertz spectra of conductivity and dielectric permittivity of the Ba(Fe<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Ni<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>)<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>As<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> thin films with different Ni concentrations. A comprehensive analysis of the experimental data was performed in the framework of the simple three-band Eliashberg model under the assumption that the superconducting coupling mechanism is mediated by antiferromagnetic spin fluctuations. The results of independent experiments support the choice of model parameters. Based on calculations of the temperature dependences of superconducting gaps, we may conclude that the obtained results are compatible with the scenario, in which Ba(Fe<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Ni<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>)<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>As<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> is a multiband superconductor with s<span><math><msub><mrow></mrow><mrow><mo>±</mo></mrow></msub></math></span>-wave pairing symmetry.</div></div>","PeriodicalId":16811,"journal":{"name":"Journal of Physics and Chemistry of Solids","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Physics and Chemistry of Solids","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022369724004992","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The uncertainty of the nature of the normal state and superconducting condensate of unconventional superconductors continues to stimulate considerable speculation about the mechanism of superconductivity in these materials. Of particular interest are the type of symmetry of the order parameter and the basic electronic characteristics of the superconducting and normal states. We report the derivation of temperature dependences of the superconducting condensate plasma frequency, superfluid density, and London penetration depth by measuring terahertz spectra of conductivity and dielectric permittivity of the Ba(FeNi)As thin films with different Ni concentrations. A comprehensive analysis of the experimental data was performed in the framework of the simple three-band Eliashberg model under the assumption that the superconducting coupling mechanism is mediated by antiferromagnetic spin fluctuations. The results of independent experiments support the choice of model parameters. Based on calculations of the temperature dependences of superconducting gaps, we may conclude that the obtained results are compatible with the scenario, in which Ba(FeNi)As is a multiband superconductor with s-wave pairing symmetry.
期刊介绍:
The Journal of Physics and Chemistry of Solids is a well-established international medium for publication of archival research in condensed matter and materials sciences. Areas of interest broadly include experimental and theoretical research on electronic, magnetic, spectroscopic and structural properties as well as the statistical mechanics and thermodynamics of materials. The focus is on gaining physical and chemical insight into the properties and potential applications of condensed matter systems.
Within the broad scope of the journal, beyond regular contributions, the editors have identified submissions in the following areas of physics and chemistry of solids to be of special current interest to the journal:
Low-dimensional systems
Exotic states of quantum electron matter including topological phases
Energy conversion and storage
Interfaces, nanoparticles and catalysts.