We report the results of a study of the temperature-dependent thermal difference reflectance (TDR) spectra of five different high-temperature superconducting cuprates, Tl{dollar}rmsb2Basb2Casb2Cusb3Osb{lcub}10{rcub}{dollar}, Tl{dollar}rmsb2Basb2CaCusb2Ossb8{dollar}, (BiPb){dollar}rmsb2Srsb2Casb2Cusb3Osb{lcub}10{rcub}{dollar}, HgBa{dollar}rmsb2CaCusb2Osb6{dollar} and YBa{dollar}rmsb2Cusb3Osb7{dollar}. Thermal difference reflectance spectroscopy is a technique by which it is possible to measure the temperature-dependent changes in a material's reflectance to 0.005%. By measuring the TDR spectra of the cuprate superconductors at several temperatures above and below each material's critical temperature, it is possible to gain information on the material's normal state optical parameters, and on the energy-dependence of the electron-boson coupling function that is responsible for superconductivity.; From the TDR spectta collected at room temperature, the value of the screened plasma frequency, {dollar}tildeomegasb{lcub}rm p{rcub}{dollar}, for each material has been graphically determined. The values for {dollar}tildeomegasb{lcub}rm p{rcub}{dollar} fall between 0.9 and 1.5 eV and are in good agreement with literature values. From the normal state TDR spectra collected at several temperatures, it has been found that the amplitude of the characteristic optical structure near the screened plasma frequency of each sample varies approximately linearly with temperature, T, indicating that the temperature-dependent normal state scattering rate in these materials scales with temperature as T{dollar}sp2{dollar}.; From the TDR spectra collected above and below the critical temperature of each sample, the superconducting to normal state reflectance ratio, R{dollar}sb{lcub}rm S{rcub}{dollar}/R{dollar}sb{lcub}rm N{rcub}{dollar}, has been obtained. In all of these spectra, there are significant deviations from unity in R{dollar}sb{lcub}rm S{rcub}{dollar}/R{dollar}sb{lcub}rm N{rcub}{dollar} at photon energies on the order of 2.0 eV. Both the temperature dependence and location of this structure in the R{dollar}sb{lcub}rm S{rcub}{dollar}/R{dollar}sb{lcub}rm N{rcub}{dollar} spectra may be described by solving the Eliashberg integral equations with an electron-boson coupling function that includes both an electron-phonon interaction and a high-energy electron-boson interaction. This high energy interaction is located at approximately the energies of known charge transfer excitations in these materials ({dollar}sim{dollar}2.0eV). We find remarkably good agreement between the experimental data and the results of our calculations based upon this description of the superconducting state.
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机译：我们报告了对五个不同的高温超导铜酸盐Tl {dollar} rmsb2Basb2Casb2Cusb3Osb {lcub} 10 {rcub} {dollar}，Tl {dollar} rmsb2Basb2Casb2Casb2Casb2Casb2Cusb3Osb {lcub}美元}，（BiPb）{dollar} rmsb2Srsb2Casb2Cusb3Osb {lcub} 10 {rcub} {dollar}，HgBa {dollar} rmsb2CaCusb2Osb6 {dollar}和YBa {dollar} rmsb2Cusb3Osb7 {dollar}。热差反射光谱法是一种可以测量材料的反射率随温度变化至0.005％的技术。通过在高于和低于每种材料的临界温度的几个温度下测量铜酸盐超导体的TDR光谱，可以获得有关材料的常态光学参数以及负责电子玻色子耦合功能的能量依赖性的信息用于超导。从室温下收集的TDR光谱中，已通过图形确定了每种材料的筛选血浆频率{dollar} tildeomegasb {lcub} rm p {rcub} {dollar}的值。 {dollar} tildeomegasb {lcub} rm p {rcub} {dollar}的值介于0.9和1.5 eV之间，并且与文献值高度吻合。从在几个温度下收集的正常状态TDR光谱中，发现每个样品的筛选等离子体频率附近的特征光学结构的幅度随温度T线性近似变化，表明温度相关的正常状态散射速率在这些材料随温度变化为T {dollar} sp2 {dollar}。从在每个样品的临界温度之上和之下收集的TDR光谱中，超导至正常状态的反射比R {dollar} sb {lcub} rm S {rcub} {dollar} / R {dollar} sb {lcub} rm N已获得{rcub} {dollar}。在所有这些光谱中，R {dollar} sb {lcub} rm S {rcub} {dollar} / R {dollar} sb {lcub} rm N {rcub} {dollar}的单位均存在显着偏差2.0 eV的量级。温度依赖性和该结构在R {dollar} / R {dollar} sb {lcub} rm N {rcub} {dollar}光谱中的温度依赖性和位置都可以通过求解来描述具有电子-玻色子耦合函数的Eliashberg积分方程，其中包括电子-声子相互作用和高能电子-玻色子相互作用。这种高能量的相互作用大约位于这些材料中已知电荷转移激发的能量（{sim} {dol} 2.0eV）处。基于对超导状态的描述，我们发现实验数据与计算结果之间有很好的一致性。
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