Heat conduction and reversed thermal diode: The interface effect

The important role of interface collisions on the thermal-diode effect, of the two-segment lattices is studied. In the high-average temperature region, it is found that the thermal-diode effect may be significantly weaken and even annihilated. In the low-temperature region, where the thermal diode is inhibited in the collisionless case, an interesting reversed thermal diode is achieved. These behaviors are interpreted in terms of phonon-band mixing induced by interface collisions. The regime where a reversed thermal diode can be observed by resorting to the dependence of the heat current on the average temperature, and a critical temperature exists. The results proposed in this paper reveal that thermal-diode effect can be qualitatively influenced if the interface collisions could not be neglected.

Figure 1

The evolution of the positions of interface particles $A$ and $B$ for (a) the collisionless case, and (b) in the presence of elastic collisions. The equilibrium positions of particles $A$ and $B$ are set as 0 and 1, respectively. Here, $N=100$, $k_{int}=0.05$, $T_0=0.07$, and $\Delta =-0.5$.

Figure 2

The heat flow $J$ versus $\Delta$ for different values of $T_0$: Squares in (a) denote the results for $T_0=0.07$, and circles in (b) for $T_0=0.09$. Solid symbols give the result following Ref. [10], while the empty ones denote the results by taking into account the collisions. For the sake of clarity, the solid squares and circles in Figs. 1a, 1b are enlarged in (c) and (d), respectively. Here the parameters are $N=100$ and $k_{int}=0.05$. The lines are drawn to guide eyes.

Figure 3

(a) and (b) show the single-particle spectrum of interface particles $A$ and $B$ for the collisionless case in Fig. 1a. While (c) and (d) give the phonon bands of particles $A$ and $B$ for the case in Fig. 1b.

Figure 4

Temperature profile for $T_0=0.07$. Solid symbols show the results in the presence of collisions, while empty symbols give the results for collisionless case. Here, $N=100$ and $k_{int}=0.05$.

Figure 5

The heat flow $J$ versus $\Delta$ for $T_0=0.02$. Solid squares give the result in the collisionless case, while the empty ones denote the results in the presence of the collisions. $N=100$ and $k_{int}=0.05$. The lines are drawn to guide eyes.

Figure 6

The evolution the positions of interface particles $A$ and $B$ for the case of (a): $\Delta =0.5$ and (b): $\Delta =-0.5$, where the hard-core collisions are taken into account. $N=100$, $k_{int}=0.05$ and $T_0=0.02$.

Figure 7

The single-particle spectrum of interface particles $A$ and $B$ corresponding to Fig. 6a $\left(\Delta =0.5\right)$ are shown in (a) and (b). The phonon bands of $A$ and $B$ when $\Delta =-0.5$ are given in (c) and (d). $N=100$, $k_{int}=0.05$ and $T_0=0.02$.

Figure 8

Temperature profile for $T_0=0.02$ in the presence of collisions. Here, $N=100$ and $k_{int}=0.05$

Figure 9

The heat flow $J_{+}$ (denoted by squares) and the flow $\left|J_{-}\right|$ (denoted by triangles) versus the system temperature $T_0$.

Figure 10

The heat flow $J_{+}$ (denoted by squares) and the flow $\left|J_{-}\right|$ (denoted by circles) versus the system size $N$ for (a) $T_0=0.07$ and (b) $T_0=0.02$.