Thermal Rectification and Thermal Logic Gates in Graded Alloy Semiconductors

Abstract

Classical thermal rectification arises from the contact between two dissimilar bulk materials, each with a thermal conductivity (k) with a different temperature dependence. Here, we study thermal rectification in a Si(1−x)Gex alloy with a spatial dependence on the atomic composition. Rectification factors (R = kmax/kmin) of up to 3.41 were found. We also demonstrate the suitability of such an alloy for logic gates using a thermal AND gate as an example by controlling the thermal conductivity profile via the alloy composition. This system is readily extendable to other alloys, since it only depends on the effective thermal conductivity. These thermal devices are inherently advantageous alternatives to their electric counterparts, as they may be able to take advantage of otherwise undesired waste heat in the surroundings. Furthermore, the demonstration of logic operations is a step towards thermal computation.

Tunable Heat-Flux Rectification in Graded Nanowires in Non-Linear Guyer-Krumhansl Regime

“…We obtained a rectification coefficient R = 2.77. A comparison with the results in Table 1 shows that the increment of the intensity of the heat flux, together with the presence of nonlinear and nonlocal effects, gives rise to a reduction of R. A comparison with the results in [38] confirms such a situation. Therein, the rectification coefficient for Si 1−c Ge c alloys has been calculated under the hypothesis of the validity of the Fourier law.…”

A one-way street for phonon transport: past, present and future of solid-state thermal rectification

“…Higher rectification factors were later obtained in other systems with a gradual variation of some structural feature, namely graphene [13] and Si membranes [14], presenting an asymmetric distribution of defects. The behavior was well understood and backed by theoretical calculations [19][20][21][22], to the extent that more elaborated designs that could yield enhanced rectifications were proposed [23]. Those devices behaved, at least to some extent, as thermal diodes because of the difference between accumulating defects next to the cold or to the hot side: in the former case they reduce considerably the conductance by adding additional scattering; in the latter case phonon scattering is already dominated by high temperature anharmonic effects and adding structural imperfections has little effect.…”

Dynamic response of a thermal transistor to time-varying signals

“…Over the years, various thermal transistors based on near-field thermal radiation, [6] nonlinear phonon conduction in nanoscale systems, [7,8] nanoscale confined fluids, quantum electronic systems, [9][10][11][12][13] and Josephson junction between different superconductors [14,15] have been designed and some of them have been experimentally demonstrated. [16][17][18][19][20][21] In many cases, with the help of a suitably designed electromagnetic field, the thermal control functions can be realized more easily.…”