Electric field dependence of thermal conductivity in bulk systems and nanosystems with charged mobile defects

Abstract

In systems with charged mobile defects, application of an external electric field modifies the spatial distribution of defects. We obtain the corresponding dependence of the thermal conductivity on the electric field due to the redistribution of defects, both in bulk systems (heat transfer described by Fourier’s law) and in nanosystems (heat transfer described by phonon hydrodynamics). We consider the electric field transverse to the heat flux as well as the electric field parallel to the heat flux; in the latter case, we consider a superlattice composed of alternating layers with defects and without defects. For transverse electric fields, the effective thermal conductivity is increased in bulk systems and decreased in nanosystems. This dependence on the field would allow us to control heat transport in an easy and reversible way without modifying the material.

Non-Equilibrium Thermodynamics of Heat Transport in Superlattices, Graded Systems, and Thermal Metamaterials with Defects

“…Because of the influence of defects, stress, and structures on the transport coefficients, the action of external fields on these components of the system has a strongly nonlinear effect. In particular, the dependence of the electrical conductivity on an applied electric field in some kinds of polarized systems or in systems with charged defects (see [46,[201][202][203][204][205]) may open new ways to control the heat flux in an easily tunable way. We have considered a number of possible new applications suggested by the present formalism.…”

“…Such systems, which we describe below, are opening new perspectives on material sciences, either at macroscopic, mesoscopic or nanoscopic scales. We further consider the influence of defects (point defects or line defects) and of applied stress, both in the case that the defects are fixed and in the case they may move [41][42][43][44][45][46][47][48][49][50][51][52][53][54]. These topics have received a further impetus with the possibility of nanomanipulation of the systems by means of nanotechnology techniques; to describe heat transport in such nanosystems, one must go beyond Fourier's law, which is a very active practical and theoretical topic [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69].…”

“…A macroscopic nonequilibrium model for semiconductor crystals and superlattices with defects, formulated in previous papers [41][42][43][44][45][46][47], is enlarged, in the framework of rational extended irreversible thermodynamics with internal variables (see also [76], where the same procedure is used), where the dissipation inequality is exploited using Liu's procedure and additional rate equations for dissipative fluxes and the defects are given as ansatzes in the form of balance Equations (see (44) in Section 4 [70][71][72][73][74]).…”