  Spin-orbit coupling in solids describes an interaction between an electron's
spin, an internal quantum-mechanical degree of freedom, with its linear
momentum, an external property. Spin-orbit interaction, due to its relativistic
nature, is typically small in solids, and is often taken into account
perturbatively. It has been recently realized, however, that materials with
strong spin-orbit coupling can lead to novel states of matter such as
topological insulators and superconductors. This exciting development might
lead to a number of useful applications ranging from spintronics to quantum
computing. In particular, theory predicts that narrow band gap semiconductors
with strong spin-obit coupling are a suitable platform for the realization of
Majorana zero-energy modes, predicted to obey exotic non-Abelian braiding
statistics. The pursuit for realizing Majorana modes in condensed matter
systems and investigating their exotic properties has been a subject of
intensive experimental research recently. Here, we demonstrate the first
realization of gate-defined wires where one-dimensional confinement is created
using electrostatic potentials, on large area InAs two dimensional electron
systems (2DESs). The electronic properties of the parent 2DES are fully
characterized in the region that wires are formed. The strength of the
spin-orbit interaction has been measured and tuned while the high mobility of
the 2DES is maintained in the wire. We show that this scheme could provide new
prospective solutions for scalable and complex wire networks.
