Figure 7.

(Color online) Schematic representation of anomalous open-boundary spectrum. (a,b) The number of the non-zero imaginary part of the open-boundary eigenvalues versus the system size, which displays the oscillation behavior. (c) The open-boundary eigenvalues and the corresponding continuum bands. From (a–c) ${\gamma }_1=-{\gamma }_2={\gamma }_3=-{\gamma }_4={\displaystyle \frac{1}{100}}$. (d) The number of the non-zero imaginary part of the open-boundary eigenvalues versus the system size, which increases fleetly and increasingly with ${\gamma }_1=-{\gamma }_2={\gamma }_3=-{\gamma }_4=1$. (e,f) The number of the non-zero imaginary part of the open-boundary eigenvalues versus the system size, which exhibits the oscillation behavior as well. (g) The open-boundary eigenvalues and the corresponding continuum bands. From (e–g) ${\gamma }_1=-{\gamma }_2={\gamma }_3={\gamma }_4={\displaystyle \frac{1}{100}}$. (h) The number of the non-zero imaginary part of the open-boundary eigenvalues versus the system size, which also increases fleetly and increasingly with ${\gamma }_1=-{\gamma }_2={\gamma }_3={\gamma }_4=1$. The common parameters are $t_1=1$, $t_2={\displaystyle \frac{6}{5}}$, and $t_3={\displaystyle \frac{7}{5}}$.