<報文>天然黄鉄鉱の半導体的特性(第2報) : 主として低温度領域での特性と天然結晶の特徴に関して

概要

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Measurements of electrical properties of pyrite crystals were made at temperatures down to 1.3°K with n-type natural crystals. With the temperature variation from 300°K to 4.2°K, resistivity values are slightly varied for some crystals but increased by 30 times for another crystal. Hall mobility is also varied slightly for the former crystals and decreased about 1/30 times for the latter. Hall coefficients are not different so much at the temperatures of 300°K and 4.2°K, and those absolute values show a maximum near 30°K and over. Temperature variations of resistivity, mobility and Hall coefficient are small below 4.2°K, and this metallic conduction is attributed to the impurity-band conduction, however, the activation energy ΔE estimated by assuming ρ=ρ_0 exp (ΔE/kT) decreases with the increasing impurity concentration (N_D-N_A). Activation energy of a donor to the conduction band is estimated to be 0.005 eV at the impurity concentration (N_D-N_A) of 8×10^<16>cm^<-3>, and tends to decrease with the increasing concentration. Negative magnetoresistance was observed at 4.2°K and the minimum values which appear at the appropriate strengths of magnetic fields show a tendency of increase with the increasing concentration. The cause of magnitude variety of resistivity for the natural crystal is investigated by introducing a compensation.
東北大学の論文
1972-11-15