Probing the minigap in topological insulator-based Josephson junctions under radio frequency irradiation<xref rid="cpb_28_12_127402fn1" ref-type="fn">*</xref><fn id="cpb_28_12_127402fn1"><label>*</label><p>Project supported by the National Basic Research Program of China (Grant Nos. 2016YFA0300601, 2017YFA0304700, and 2015CB921402), the National Natural Science Foundation China (Grant Nos. 11527806, 91221203, 11174357, 91421303, and 11774405), and the Strategic Priority Research Program B of the Chinese Academy of Sciences (Grant Nos. XDB07010100 and XDB28000000), and the Beijing Municipal Science & Technology Commission, China (Grant No. Z191100007219008).</p></fn>

Probing the minigap in topological insulator-based Josephson junctions under radio frequency irradiation**

Project supported by the National Basic Research Program of China (Grant Nos. 2016YFA0300601, 2017YFA0304700, and 2015CB921402), the National Natural Science Foundation China (Grant Nos. 11527806, 91221203, 11174357, 91421303, and 11774405), and the Strategic Priority Research Program B of the Chinese Academy of Sciences (Grant Nos. XDB07010100 and XDB28000000), and the Beijing Municipal Science & Technology Commission, China (Grant No. Z191100007219008).

Yang Guang^{1, 2}, Lyu Zhaozheng^{1, 2}, Zhang Xiang^{1, 2}, Qu Fanming^{1, 3, 4, †}, Lu Li^{1, 2, 3, 4, 5, ‡}

Shapiro maps in an Al–Bi₂Te₃–Al junction. (a) Differential resistance dV_J/dI_J as a function of rf power P_rf and direct bias current I_J, measured at rf frequency f_rf = 0.5 GHz. (b) The same data as in (a), but replotted as a function of rf power P_rf and direct voltage V_J across the junction in units of hf_rf/2e. Evenly spaced Shapiro steps can be seen. (c) Simulated dV_J/dI_J based on the RSJ model. (d) The same simulated dV_J/dI_J as shown in (c), but in a wider range of rf power. The black line represents the critical supercurrent I_c, and the red curve represents the sum of the critical supercurrent I_c and the amplitude of the rf-driving current I_rf0.