  We report on an experimental study of the spin-orbit interaction (SOI) in an
epitaxially grown free-standing InAs nanosheet in a dual-gate field-effect
device. Gate-transfer characteristic measurements show that independent tunings
of the carrier density in the nanosheet and the potential difference across the
nanosheet can be efficiently achieved with use of the dual gate. The quantum
transport characteristics of the InAs nanosheet are investigated by
magnetoconductance measurements at low temperatures. It is shown that the
electron transport in the nanosheet can be tuned from the weak antilocalization
to the weak localization and then back to the weak antilocalization regime with
a voltage applied over the dual gate without a change in carrier density. The
spin-orbit length extracted from the magnetoconductance measurements at a
constant carrier density exhibits a peak value at which the SOI of the Rashba
type is suppressed and the spin relaxation due to the presence of an SOI of the
Dresselhaus type in the nanosheet can be revealed. Energy band diagram
simulations have also been carried out for the device at the experimental
conditions and the physical insights into the experimental observations have
been discussed in light of the results of simulations.
