Band Structure of Gray Tin

In this Letter a new model for the band structure of n-Sn is proposed which is compatible with the experimental results reported on this material and particularly with the measurements of magnetoresistance and the pressure dependence of the conductivity (o) and Hall coefficient (R) which have been in relatively poor agreement with models previously suggested. Theoretical calculations of Herman, ' and of Liu and Bassani, ' predict the lowest conduction band to be at the center of the Brillouin zone with I', (I', ' single group representation) symmetry, and the highest valence band to have I', + (I»' single group representation) symmetry. This is in agreement with magnetoresistance measurements' near 77 K and with oscillatory magnetoresistance data' at and below 4'K, both of which show no measurable anisotropy. However, several unrelated measurements require the presence of conduction-band minima of (111) symmetry. Magnetoresistance measurements near 200 K by