Università
Cattolica del Sacro Cuore – Sede di Brescia
Dr. Stefano Roddaro
ABSTRACT
I
shall present a novel technique for the manipulation of the energy spectrum of
hard-wall quantum dots obtained in axially-heterostructured
InAs/InP nanowires. By using two local gate electrodes in a
single-electron transistor (see figure), a strong transverse electric field is
induced in the dot and a controlled modification of the electron orbitals is obtained. Such experimental approach is used to
significantly enhance the single-particle energy spacing between the first two
quantum levels in the electronic island and thus to increment the working
temperature of the InAs/InP
single-electron transistors from 4K up to ~50K. Preliminary results also
indicate that the same technique can be exploited to tune the total spin of the
dot when an energy degeneracy is induced between two partially filled orbitals. A strong and electrostatically-driven
single-triplet transition is demonstrated and controlled up to a temperature of
20K. Perspectives for the investigation of spin physics in nanowires
are also discussed