Geometric effect on near-field heat transfer analysis using efficient graphene and nanotube models
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THE EUROPEAN PHYSICAL JOURNAL B
Regular Article
Geometric effect on near-field heat transfer analysis using efficient graphene and nanotube models Kristo Nugraha Lian 1,a and Jian-Sheng Wang 2 1 2
Centre for Quantum Technologies, National University of Singapore, Singapore 117543, Republic of Singapore Department of Physics, National University of Singapore, Singapore 117551, Republic of Singapore Received 30 March 2020 / Received in final form 4 June 2020 Published online 15 July 2020 c EDP Sciences / Societ`
a Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature, 2020 Abstract. Following the recent research enthusiasm on the effect of geometry on near-field heat transfer (NFHT) enhancement, we present an analysis based on simplified yet highly efficient graphene and nanotube models. Two geometries are considered: that of two parallel infinite “graphene” surfaces and that of a one-dimensional infinite “nanotube” line in parallel with an infinite surface. Due to its symmetry, the former is in principal simpler to analyze and even so, earlier works suggested that the application of a full model in this problem still demands heavy computations. Among other findings, our simplified computation – having successfully replicated the results of relevant earlier works – suggests a sharper NFHT enhancement dependence on distance for the line-surface system, namely J ∼ d−5.1 as compared to J ∼ d−2.2 for the parallel surface. Such comparisons together with applications of our efficient approach would be the important first steps in the attempt to find a general rule describing geometric dependence of NFHT.
1 Introduction In light of recent advancements in nano-materials and design, an amendment to the conventional theory of radiative heat transfer discovered in the 1900s [1] is imperative. Concerning distances of the order of thermal wavelength λth = ~c/kB T or less, electromagnetic waves no longer hold the crucial role as the sole heat transfer mediator; interactions of electrons, plasmons and polaritons begin to gain importance [2–4]. In this regard, research interests grow in the field of near-field radiative heat transfer (NFHT), which was pioneered in the 1970s when Polder and van Hove [5] developed the idea of applying the formalism of fluctuational electrodynamics [6] into materials property problem [7]. Application of this idea on NFHT follows the establishment of the analogue of Poynting vector [8] in the case of non-photonic heat transfer using the Maxwell’s equations. On the practical spectrum, these theoretical predictions have in fact been realized several years earlier [9,10] while new advanced thermal devices, e.g., thermal microscopy (STM), photovoltaic systems, and thermal transistors are unceasingly being developed based on the NFHT principles [11,12]. Following some previous works on NFHT [2,7], in this work our analysis considers only the contribution of charge fluctuations and their corresponding “scalar photons” from the scalar field. This point has indeed been discussed a
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