OPTICAL-CONSTANTS OF COPPER AND NICKEL AS A FUNCTION OF TEMPERATURE
OPTICAL-CONSTANTS OF COPPER AND NICKEL AS A FUNCTION OF TEMPERATURE
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DOI：
10.1103/physrevb.11.1315
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发表时间：
1975-01-01
影响因子：
3.7
通讯作者：
CHRISTY, RW
中科院分区：
文献类型：
--
作者：
JOHNSON, PB;CHRISTY, RW
在78、293和423 K的温度下，在0.5-6.5 eV的光谱范围内，通过对真空蒸发薄膜的反射和透射测量，确定了铜和镍的光学常数。镍的介电常数的虚部几乎与温度无关，但铜的介电常数的虚部随着温度的增加而增加，在带内区域低于2 eV，在带间区域低于4 eV。根据德鲁德自由电子表达式的解释低于2 eV的增加表明弛豫时间的温度和频率依赖性，这是不完全解释。然而，如果通过在近自由电子带之间的跃迁中引入德拜-沃勒因子来修正威廉姆斯、雅纳克和莫鲁齐的零温理论，就可以很大程度上理解带间区域的热行为。
The optical constants were determined for copper and nickel from reflection and transmission measurements on vacuum-evaporated thin films, in the spectral range 0.5-6.5 eV and at temperatures of 78, 293, and 423 K. The imaginary part of the dielectric constant was nearly independent of temperature for nickel, but for copper it increased with temperature in the intraband region below 2 eV and decreased above 4 eV in the interband region. Interpretation of the increase below 2 eV according to the Drude free-electron expression suggests a temperature and frequency dependence of the relaxation time, which is not completely explained. The thermal behavior in the interband region can be largely understood, however, if the zero-temperature theory of Williams, Janak, and Moruzzi is modified by including a Debye-Waller factor in transitions between nearly-free-electron-like bands.