Optical probing of the minigap in InAs/GaSb superlattices

We report large modulations in the far infrared absorption of semimetallic InAs/GaSb superlattices in parallel field. The strong absorption is attribu ted to direct transitions across the minigap at the point where the electro n and hole dispersions anticross. The measured minigap energy is found to b e in the range 3-10 meV depending on the structure of the sample. The optic al results are compared to parallel field magnetoresistance measurements an d also to theory using an 8 band k . p calculation. (C) 1998 Elsevier Scien ce B.V. All rights reserved.