Room-temperature Hall mobilities of natural single crystals of iron pyrite with carrier concentrations of approximately ${10}^{18}$/${\mathrm{cm}}^3$ were found to be approximately 100 ${\mathrm{cm}}^2$/volt-sec for electrons and 1 for holes. Resistivity as a function of temperature was measured on six samples in the range from -196°C to 403°C; from this measurement the width of the forbidden band was estimated to be 1.2 ev.

• Received 21 June 1954

DOI:https://doi.org/10.1103/PhysRev.96.593