  The development of spin-based applications of topological insulators requires
the knowledge and understanding of spin texture configuration maps as they
change via gating in the vicinity of an isolated Dirac node. An isolated
(graphene-like) Dirac node, however, does not exist in Bi2Te3. While the
isolation of surface states via transport channels has been promisingly
achieved in Bi2Te3, it is not known how spin textures modulate while gating the
surface. Another drawback of Bi2Te3 is that it features multiple band crossings
while chemical potential is placed near the Dirac node (at least 3 not one as
in Bi2Se3 and many other topological insulators) and its buried Dirac point is
not experimentally accessible for the next generation of experiments which
require tuning the chemical potential near an isolated (graphene-like) Dirac
node. Here, we image the spin texture of Bi2Te3 and suggest a simple
modification to realize a much sought out isolated Dirac node regime critical
for almost all potential applications (of topological nature) of Bi2Te3.
Finally, we demonstrate carrier control in magnetically and nonmagnetically
doped Bi2Te3 essential for realizing giant magneto-optical effects and
dissipationless spin current devices involving a Bi2Te3-based platform.
