[PCP2] Physics and Chemistry2

[PCP2-11] Temperature-dependent dielectric response and heat transfer suppression in high-temperature superconductors

*Bixi Li^1,2, Zichun Huang^1,2, Liancheng Xie^1,2, Linjie Zhang^1,2, Fuzhi Shen¹, Hengcheng Zhang¹, Hao Zhang¹ (1. Key Laboratory of Cryogenic Science and Technology, TIPC, CAS (China), 2. University of Chinese Academy of Sciences (China))

Keywords:

High-temperature superconductors,Dielectric function,Heat transfer suppression

In recent years, high-temperature superconductors (HTSCs) have demonstrated exceptional capabilities for controlling near-field radiative heat transfer (NFRHT), particularly through their pronounced suppression of thermal radiation below the superconducting transition temperature. This effect opens new opportunities for non-contact thermal management technologies. To better understand this phenomenon and optimize thermal management strategies, it is essential to investigate the attenuation mechanism of NFRHT in the superconducting state. In this study, we employ the framework of fluctuation electrodynamics combined with Maxwell’s equations to calculate the NFRHT between two parallel YBCO (YBa₂Cu₃O_6.95) planes, with the dielectric function serving as the key parameter governing heat transfer characteristics. Conventional models often assume that the free-electron scattering rate (damping rate) vanishes in the superconducting state. However, this neglects the residual dissipative contribution from normal electrons that persist below the transition temperature. To address this, we adopt a two-fluid model in which the damping rate of the normal electron-pair component is treated as a temperature-dependent parameter, enabling a more evident description of the dielectric response during the superconducting transition. Our results show that while the imaginary part of YBCO’s dielectric function in the superconducting state agrees with traditional predictions, the effective damping rate evolves dynamically as temperature decreases. We further derive a quantitative relationship between radiative heat flux and the superconducting electron-pair fraction, and establish a temperature-dependent damping rate model for the superconducting state. This work not only provides theoretical support for integrating HTSCs into near-field thermal management systems but also offers potential insights into the thermodynamic mechanisms underlying superconductivity.