Infrared Absorption of Indium Antimonide

Infrared absorption in InSb near the absorption edge has been interpreted as the superposition of two indirect transitions requiring phonons of 100^∘{} and 30^∘{}, the former transition involving the smaller electronic energy gap. The first transition is consistent with a band scheme having electrons at the center of the zone and holes either at the corner of the zone or about halfway along the [1,1,1] line. The other transition may indicate a second hole with an energy gap about 0.025 ev larger than that of the first.