Zhao et al. Reply:

Figure 1

(a) The surface gap as a function of $\ell$. Our results (black solid) recover those (red dashed) from Fig. 1(a) in Ref. [1]. Inset: $m_{\mathrm{surf}}$ becomes singular around ${\ell }_c\approx 3.6$. (b) $B/D$ decreases with increasing $\ell$ without bound. Inset: $B=0$ around ${\ell }_c\approx 3.6$, leading to the singular $m_{\mathrm{surf}}$.