Near-field radiative heat transfer between high-temperature superconductors

Abstract

Near-field radiative heat transfer (NFRHT) management can be achieved using high-temperature superconductors. In this work, we present a theoretical study of the radiative heat transfer between two $$\hbox {YBa}_2\hbox {Cu}_3\hbox {O}_{6.95}$$ YBa 2 Cu 3 O 6.95 (YBCO) slabs in three different scenarios: Both slabs either in the normal or superconducting state, and only one of them below the superconductor critical temperature $$T_c$$ T c . The radiative heat transfer is calculated using Rytov’s theory of fluctuating electrodynamics, while a two-fluid model describes the dielectric function of the superconducting materials. Our main result is the significant suppression of the NFRHT when one or both of the slabs are superconducting, which is explained in terms of the detailed balance of the charge carriers density together with the sudden reduction of the free electron scattering rate. A critical and unique feature affecting the radiative heat transfer between high-temperature superconductors is the large damping of the mid-infrared carriers which screens the surface plasmon excitation.

Role of Electronic Relaxation Rates in the Casimir Force between High-Tc Superconductors

“…The dielectric response of YBa 2 Cu 3 O 6.95 with T c = 93 K is thus specified by a diagonal dielectric tensor ε = diag(ε ab , ε ab , ε c ) [39,40], where its components have been characterized through a number of experimental studies [38,[41][42][43][44][45]. Explicit calculations incorporating the resulting parameterizations for ε ab (ω) and ε c (ω) show that the c-axis optical response leads to negligible contributions in the evaluation of frequency-integrated quantities, such as the heat flux between YBCO plates at different temperatures [46] or the Casimir force per unit area considered in this work. Therefore, to ease the interpretation of the derived results, in the following, we limit our analysis by contemplating only the ab-plane permittivity.…”

Casimir Forces Out of Thermal Equilibrium Near A Superconducting Transition

“…The number of optical phonons considered in the dielectric response is N ph = 6, and the parameters S ph;ab,k , ω ph;k , and γ ph;k , are presented in Ref. 31 .…”

“…Here, ω ps (2K) = 1.14 × 10 15 rad/s, while the parameters ε ∞ , Ω mir , ω mir , and Γ mir are the identical to those considered in the normal phase, while the phonon parameters presented in Ref. 31 are very similar as those involved in the normal case.…”

“…With that purpose, we calculate the Casimir pressure between two YBCO plates at different local temperatures by means of the formalism presented by Antezza 27 , taking into account the temperature dependence of the dielectric function around the superconducting phase transition. Similar methods based on the evaluation of the Poynting vector have been recently employed by us to evaluate the near-field radiative heat transfer between high-T c superconducting (HTSC) plates 31,32 . A central feature in that analysis is the role of evanescent surface plasmon modes, which may hybridize when the plates are close enough, inducing nontrivial features like the enhancement of the heat flux by thin SC films.…”

Casimir forces out of thermal equilibrium near a superconducting transition

“…We employ the formalism presented by Antezza 27 , taking into account the temperature dependence of the dielectric function around the superconducting phase transition. Similar methods based on the evaluation of the Poynting vector have been recently employed by us to evaluate the near-field radiative heat transfer between high- superconducting (HTSC) plates 31 , 32 . A central feature in that analysis is the role of evanescent surface plasmon modes, which may hybridize when the plates are close enough, inducing nontrivial features like the enhancement of the heat flux by thin SC films.…”