(color online) Equilibrium transmission spectrum for the armchair (5,0) BNT encapsulated with silicon (a), germanium (b), and boron (c) nanowires and zigzag (3,3) BNT encapsulated with silicon (d), germanium (e), and boron (f) nanowires. The insets illustrate the structure of these BNTs respectively. The Fermi level is set to zero.