  We study the spin-orbit interaction (SOI) in InAs/ GaSb and InAs quantum
wells. We show through temperature- and gate-dependent magnetotransport
measurements of weak antilocalization that the dominant spin-orbit relaxation
mechanism in our low-mobility heterostructures is Elliott-Yafet and not
Dyakonov-Perel in the form of the Rashba or Dresselhaus SOI as previously
suggested. We compare our findings with recent work on this material system and
show that the SOI length lies within the same range. The SOI length may be
controlled using an electrostatic gate, opening up prospects for developing
spintronic applications.
