Prischepa S L, Kushnir V N
Belarusian State University of Informatics and Radioelectronics, P. Browka 6, 220013 Minsk, Belarus.
Belarusian State University, Nezalezhnasci av. 4, 220030 Minsk, Belarus.
J Phys Condens Matter. 2023 May 10;35(31). doi: 10.1088/1361-648X/acc6ae.
Various aspects of phonon spectrum changes in nanostructured phonon-mediated superconductors are considered. It is shown how, with the development of experimental techniques and, accordingly, obtaining new results, the understanding of the influence of the surface and nanoscale on the magnitude of the electron-phonon interaction and the critical temperaturechanged and deepened. The review is organized as follows. After the, in thepart we give the quick theoretical background for the description of superconductivity within the framework of various formalisms. In thepart we describe the properties of nanostructured (granular) thin films paying attention to the impact of grain sizes and methods of deposition on thevalue. The role of material parameters is underlined and different aspects of the behavior of granular thin films are discussed. In thesection the impact of external sources of modification of the phonon spectra like noble gases and organic molecules are considered. Problems and progress in this area are discussed. Thepart is dedicated to the phonon modification and related quantum size effects in nanostructured superconductors. In thepart we review the results of direct evidence of phonon softening in nanostructured superconductors and in thesection we discuss a possible alternative description of the superconducting properties of nanostructured superconductors related to the concept of metamaterials. In theandparts we review the impact of substrates with lattice mismatched parameters and graphene sheets, respectively, on the modification of the phonon spectrum and enhancement of superconductivity in various superconducting thin films. Finally, in the lastsection we consider the nonequilibrium superconductivity driven by femtosecond pulses of light, which leads to generation of coherent phonons and to a significant increase in the critical temperature in a number of superconducting materials.
本文考虑了纳米结构声子介导超导体中声子谱变化的各个方面。展示了随着实验技术的发展以及相应地获得新结果，对表面和纳米尺度对电子 - 声子相互作用强度和临界温度的影响的理解是如何发生变化和深化的。综述内容组织如下。在第一部分，我们给出了在各种形式体系框架内描述超导性的快速理论背景。在第二部分，我们描述了纳米结构（颗粒状）薄膜的性质，重点关注晶粒尺寸和沉积方法对超导转变温度值的影响。强调了材料参数的作用，并讨论了颗粒状薄膜行为的不同方面。在第三部分，考虑了诸如稀有气体和有机分子等外部声子谱改性源的影响。讨论了该领域的问题和进展。第四部分致力于纳米结构超导体中的声子改性及相关量子尺寸效应。在第五部分，我们综述了纳米结构超导体中声子软化的直接证据结果，在第六部分，我们讨论了与超材料概念相关的纳米结构超导体超导特性的一种可能替代描述。在第七部分和第八部分，我们分别综述了具有晶格失配参数的衬底和石墨烯片对各种超导薄膜中声子谱改性和超导增强的影响。最后，在最后一部分，我们考虑了由飞秒光脉冲驱动的非平衡超导性，这导致了相干声子的产生以及许多超导材料中临界温度的显著提高。
