  We study field-effect transistors realized from VO2 nanobeams with HfO2 as
the gate dielectric. When heated up from low to high temperatures, VO2
undergoes an insulator-to-metal transition. We observe a change in conductance
(~ 6 percent) of our devices induced by gate voltage when the system is in the
insulating phase. The response is reversible and hysteretic, and the area of
hysteresis loop becomes larger as the rate of gate sweep is slowed down. A
phase lag exists between the response of the conductance and the gate voltage.
This indicates the existence of a memory of the system and we discuss its
possible origins.
