Electric field control of Metal- insulator phase transition in
VO2 nano-wire channel Tsubasa Sasaki (Tanaka-lab) 2013/5/29 Slide 2
Contents Background Metal-insulator transition(MIT) of
strongly-correlated electron(Mott) materials (ex. VO 2 ) How to
control of MIT? Mott FET Purpose of my research Control of MIT by
electric field Principle of Mott transition My original model
Experiment Pulsed laser deposition ( PLD ) Nano imprint lithography
Result Summary Slide 3 Background strongly-correlated electron
materials ( ) VO 2 strongly-correlated electron materials ( ) VO 2
Mott insulator Temperature Impurity doping Temperature Impurity
doping Huge resistivity change (10 3 10 4 ) Huge resistivity change
(10 3 10 4 ) Metal-insulator transition(MIT) Temperature change
Impurity doping (V 3+,4+,W 6+ O 2 Slide 4 Background How to control
the MIT? Control of MIT by electric field MIT : metal-insulator
transition Porpose of my reserch Mott FET Device Gate DrainSource
VGVG Drain current Metal Slide 5 M.M.Qazilbash et al, Science 318,
1750 (2007) Phase separation with 100 nm-sized domains around
Metal-Insulator transition VO 2 Background Slide 6 Carrier doping
by electric field Advantage Doping only carrier Not impurity doping
Flexible(Electric field) Observable(Domain) Using side-gate FET
structures Control of MIT by carrier doping Purpose A Source Drain
Gate d L W Insulator Metal VO 2 Pt Slide 7 Principle Brinkman Rice
BR picture Effective mass changes dramatically n 0 =1.69x10 22 cm
-3 Effective mass changes greatly band filling is changed Features
of strongly-correlated electron system Carrier doping not silicon
Slide 8 Mott criterion Principle Mott transition Insulator Metal
Effective Bohr radius P. P. Edwards et al, J. Phys. Chem, 99 (1995)
5228 Slide 9 My original model Carrier doping amount by electric
field E g =0.12 eV k B =8.617 ev/K Carrier doping amount by thermal
excitation In fact, since the experiment at finite temperature, it
is necessary to consider the thermal excitation carrier. Mott
criterion(carrier doping) Slide 10 My original model Insulator
Metal Electric field switching Insulator Metal Slide 11
Experiment(PLD) Pulse laser deposition (PLD) ArF =193nm Al 2 O 3 VO
2 Production of thin film V 2 O 5 Slide 12 Experiment(nanoimprint)
Production of structure A optical micrograph Process 4mm 0.5mm
Slide 13 Result A AFM image optical micrograph Successful
production of side-gate FET structures VO 2 Pt Nano wire 400nm
300nm Slide 14 Summary I made an original model using temperature
parameter (T) and gate voltage (Vg) combined with the BR picture
and the Mott criterion I have successfully created side-gate FET
structures Further work Electronic propaty measurement I will
control MIT by electric field
