Casimir free energy of dielectric films: classical limit, low-temperature behavior and control
Casimir free energy of dielectric films: classical limit, low-temperature behavior and control
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介电薄膜的卡西米尔自由能：经典极限、低温行为和控制
DOI：
10.1088/1361-648x/aa718c
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
V. Mostepanenko
中科院分区：
文献类型：
--
作者：
G. L. Klimchitskaya;V. Mostepanenko
研究了真空中自支撑和沉积在金属板或介质板上的介质薄膜的Casimir自由能。结果表明，自由能的大小在很大程度上取决于所采用的计算方法是否忽略或考虑了薄膜材料的直流电导率。我们证明了在前一种情况下存在依赖于物质的经典极限，在后一种情况下存在普遍的经典极限。给出了自支撑介质膜在低温下的Casimir自由能和自由能的解析行为。根据我们的结果，如果采用忽略薄膜直流电导率的计算方法，当温度为零时，Casimir熵为零。如果考虑直流电导率，Casimir熵在零温度下取正值，这取决于薄膜的参数，即违反能斯特热定理。通过在两种计算方法的框架内考虑沉积在Au板上的SiO_2和Al_2O_3薄膜的Casimir自由能，我们认为忽略直流电导率的作用可以得到物理上正确的值。并与已知的两个平行板的位形结果进行了比较。最后，我们计算了在不同厚度的高阻硅片上沉积的SiO_2、Al_2O_3和Ge薄膜的Casimir自由能，证明了它可以是正的、负的和等于零的。考虑了激光对硅板的照射效应。讨论了所得结果在微电子薄膜方面的可能应用。
The Casimir free energy of dielectric films, both free-standing in vacuum and deposited on metallic or dielectric plates, is investigated. It is shown that the values of the free energy depend considerably on whether the calculation approach used neglects or takes into account the dc conductivity of film material. We demonstrate that there are material-dependent and universal classical limits in the former and latter cases, respectively. The analytic behavior of the Casimir free energy and entropy for a free-standing dielectric film at low temperature is found. According to our results, the Casimir entropy goes to zero when the temperature vanishes if the calculation approach with neglected dc conductivity of a film is employed. If the dc conductivity is taken into account, the Casimir entropy takes the positive value at zero temperature, depending on the parameters of a film, i.e. the Nernst heat theorem is violated. By considering the Casimir free energy of SiO2 and Al2O3 films deposited on a Au plate in the framework of two calculation approaches, we argue that physically correct values are obtained by disregarding the role of dc conductivity. A comparison with the well known results for the configuration of two parallel plates is made. Finally, we compute the Casimir free energy of SiO2, Al2O3 and Ge films deposited on high-resistivity Si plates of different thicknesses and demonstrate that it can be positive, negative and equal to zero. The effect of illumination of a Si plate with laser light is considered. Possible applications of the obtained results to thin films used in microelectronics are discussed.