Radiative Thermal Memristor

Based on the thermal hysteresis of a phase change material exchanging radiative heat with a phase invariable one, we propose a radiative thermal memristor characterized by a Lissajous curve between their exchanged heat flux and temperature difference periodically modulated in time. For a memristor with terminals of ${\mathrm{VO}}_2$ and a blackbody, it is shown that (i) the temperature variations of its memristance follow a closed loop determined by the thermal hysteresis width of ${\mathrm{VO}}_2$, and (ii) the thermal memristance on-off ratio is determined by the contrast of ${\mathrm{VO}}_2$ emissivities for its insulating and metallic phases and is equal to 3.6. The analogy of the proposed memristor to its electrical counterpart makes it promising to lay the foundations of the thermal computing with photons.

Figure 1

Scheme of a radiative thermal memristor: a PCM exchanging radiative heat with a non-PCM through a vacuum gap due to their temperature difference $\mathrm{\Delta }T(t)$ periodically modulated in time $t$.

Figure 2

Mean emissivity of ${\mathrm{VO}}_2$ for its heating and cooling processes. The dots stand for experimental data [40, 41, 48], while the lines represent the predictions of Eq. (3).

Figure 3

Time evolution of the heat flux, temperature difference, and ${\mathrm{VO}}_2$ emissivity driving the thermal radiation in the memristor shown in Fig. 1. The colored zones 1 and 3 stand for phase transitions, while zones 2 and 4 represent no phase changes. Calculations were done for $\theta =8\mathrm{K}$.

Figure 4

Lissajous $q-\mathrm{\Delta }T$ curve characterizing the thermal memristor. Regimes 1, 2, 3, and 4 correspond to the four characteristic zones highlighted in Fig. 3. Calculations were done for $\theta =8\mathrm{K}$ and different hysteresis widths $T_{0h}-T_{0c}$.

Figure 5

Closed loops of the thermal memristance associated with the Lissajous curves shown in Fig. 4. Regimes 1, 2, 3, and 4 correspond to the four characteristic time zones highlighted in Fig. 3.