  Bulk bismuth has a complex Landau spectrum. The small effective masses and
the large g-factors are anisotropic. The chemical potential drifts at high
magnetic fields. Moreover, twin boundaries further complexify the
interpretation of the data by producing extra anomalies in the extreme quantum
limit. Here, we present a study of angle dependence of magnetoresistance up to
65 T in bismuth complemented with Nernst, ultrasound, and magneto-optic data.
All observed anomalies can be explained in a single-particle picture of a
sample consisting of two twinned crystals tilted by 108$^{\circ}$ and with two
adjacent crystals keeping their own chemical potentials despite a shift between
chemical potentials as large as 68 meV at 65 T. This implies an energy barrier
between adjacent twinned crystals reminiscent of a metal-semiconductor Schottky
barrier or a p-n junction. We argue that this barrier is built by accumulating
charge carriers of opposite signs across a twin boundary.
