The Electrical Resistivity of Bismuth Single Crystals

Abstract

Measurements were made in the temperature range from -185°C to +100°C on bismuth crystals containing Pb, Sn, Sb and Te. The effects were found to be complicated but the following generalizations may be made. Decreasing temperature results in greater effectiveness of the impurity present except when the impurity concentration is such that a separation of phases occurs at low temperatures. Extremely small amounts (less than 0.03 percent) of all impurities cause a sharp increase in the resistance. The effect of larger amounts depends on the nature of the impurity. Pb and Sn continue to increase the resistance, additional Te forces the resistance to fall to lower values than that of pure Bi, additional Sb causes the initial rise of resistance to fall off and then to be slowly reestablished. More than 0.03 percent Sn and more than 0.3 percent Pb result in a negative temperature coefficient for the resistance parallel to the principal axis. In other cases the coefficient remains positive. The results may be explained on a combined theoretical and empirical basis.