{"title":"Spin fluctuations in conventional superconductors and anomalous isotope effect in PdH and PdD","authors":"","doi":"10.1016/j.physc.2024.1354602","DOIUrl":null,"url":null,"abstract":"<div><div>Spin fluctuations have been suggested to be an influence to the superconducting phenomenon, either favorably or disruptively. Consequently, we study the role of magnons in the thermodynamics of conventional superconductors proposing a relationship between magnetization and electron-magnon coupling (<span><math><msub><mrow><mi>λ</mi></mrow><mrow><mi>e</mi><mi>m</mi></mrow></msub></math></span>) for vanadium, niobium, lead, palladium, and the PdX (where <span><math><mrow><mi>X</mi><mo>=</mo></mrow></math></span> hydrogen, deuterium, and tritium) systems. We suggest a different relationship for the Coulomb pseudopotential (<span><math><msubsup><mrow><mi>μ</mi></mrow><mrow><mi>N</mi></mrow><mrow><mo>∗</mo></mrow></msubsup></math></span>), which is influenced by the characteristic frequency (<span><math><msub><mrow><mi>ω</mi></mrow><mrow><mo>ln</mo></mrow></msub></math></span>). In this way, the critical temperatures (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>) of the elements studied and the PdX compounds are very close to those reported experimentally. The PdH, PdD and PdT compounds have shown critical temperatures of 9.05 K, 12.20 K and 12.90 K, respectively. Finally, we determine the behavior of <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> for PdX under hydrostatic pressures up to 10 GPa, showing an alternative explanation for the anomalous isotope effect in PdH and PdD compounds. Our study was carried out by numerically solving the linearized Migdal-Eliashberg equations coupling the Bogoliubov-de-Gennes method, while the magnetic excitation was calculated using linear response time dependent within the Density Functional Theory, framework, both implemented in the Elk code.</div></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physica C-superconductivity and Its Applications","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0921453424001667","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PHYSICS, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
Spin fluctuations have been suggested to be an influence to the superconducting phenomenon, either favorably or disruptively. Consequently, we study the role of magnons in the thermodynamics of conventional superconductors proposing a relationship between magnetization and electron-magnon coupling () for vanadium, niobium, lead, palladium, and the PdX (where hydrogen, deuterium, and tritium) systems. We suggest a different relationship for the Coulomb pseudopotential (), which is influenced by the characteristic frequency (). In this way, the critical temperatures () of the elements studied and the PdX compounds are very close to those reported experimentally. The PdH, PdD and PdT compounds have shown critical temperatures of 9.05 K, 12.20 K and 12.90 K, respectively. Finally, we determine the behavior of for PdX under hydrostatic pressures up to 10 GPa, showing an alternative explanation for the anomalous isotope effect in PdH and PdD compounds. Our study was carried out by numerically solving the linearized Migdal-Eliashberg equations coupling the Bogoliubov-de-Gennes method, while the magnetic excitation was calculated using linear response time dependent within the Density Functional Theory, framework, both implemented in the Elk code.
期刊介绍:
Physica C (Superconductivity and its Applications) publishes peer-reviewed papers on novel developments in the field of superconductivity. Topics include discovery of new superconducting materials and elucidation of their mechanisms, physics of vortex matter, enhancement of critical properties of superconductors, identification of novel properties and processing methods that improve their performance and promote new routes to applications of superconductivity.
The main goal of the journal is to publish:
1. Papers that substantially increase the understanding of the fundamental aspects and mechanisms of superconductivity and vortex matter through theoretical and experimental methods.
2. Papers that report on novel physical properties and processing of materials that substantially enhance their critical performance.
3. Papers that promote new or improved routes to applications of superconductivity and/or superconducting materials, and proof-of-concept novel proto-type superconducting devices.
The editors of the journal will select papers that are well written and based on thorough research that provide truly novel insights.