Fig. 4. Dynamic response of HI-P nanofiber junction #3 at T = 448 K.

a Heat flow vs. temperature bias for even-number cycles. Solid and hollow signs indicate the forward and reverse directions, respectively. b Rectification factor vs. cycle number at 4.5 K and 6.5 K temperature biases. Dashed lines show the average rectification values, which are 7.5% and 11.2% at 4.5 K and 6.5 K temperature biases, respectively. The error bar of rectification is calculated from least-square fitting of the heat flow curve, which is elaborated in Supplementary Note 8.