Superconductivity in Twisted Bismuth Bilayers

Two twisted bismuth bilayers, TBB, each with 120 atoms, are studied using their electron density of states and their vibrational density of states using first-principles calculations. Metallic character at the Fermi level is found for the non-rotated sample as well as for each sample rotated 0.5°, 1.0°, 1.5°, 2.0°, 2.5°, 3.0°, 4.0°, 5.0°, 6.0°, 7.0°, 8.0°, and 10° with respect to each other. Assuming that the superconductivity is BCS-type and the invariance of the Cooper pairing potential, a maximum superconducting temperature T_C ≈1.8 K is predicted for a magic angle of 0.5° between the two bilayers, increasing the superconducting transition temperature from the experimentally measured value of 0.53 mK for the Wyckoff structure of crystalline bismuth.