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Carbon nanotubes under magnetic field and rotational deformation . Students: Alexei Zubarev *and Camelia Sold**. Coordinators***: D. Kolesnikov , V. Katkov. *Faculty of Physics, University of Bucharest. **Faculty of Physics, West University of Timisoara. - PowerPoint PPT Presentation
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Students: Alexei Zubarev *and Camelia Sold**
*Faculty of Physics, University of Bucharest
**Faculty of Physics, West University of Timisoara
Coordinators***: D. Kolesnikov, V. Katkov
***Bogoliubov Laboratory of Theoretical Physics, JINR, Dubna
Carbon nanostructures
Graphene Nanotubes Graphene pillars
Nanotubes propertiesNanotubes have a very broad range of electonic, thermal, and structural properties that change depending on the different kinds of nanotube (defined by its diameter, length, and chirality, or twist). To make things more interesting, besides having a single cylindrical wall (SWNTs), nanotubes can have multiple walls (MWNTs)--cylinders inside the other cylinders. Currently, the physical properties are still being discovered and disputed.
Electrons in nanotubesThe behavior of electrons is descibed by the Dirac equation:
Nanotubes under magnetic field
Magnetic flux:
Dirac equations for ΨT=(Ψ1 ,Ψ2) have the following form:
Magnetic barrier
Rotational deformation
α
Rotational deformation is equivalent to magnetic field
ResultsTransmission in function of rotational deformation: T(α)
L=10 , 5, 2, 1
Metallic channel
Secondary channel
m = 0
L = 0.05, 0.5, 1, 2
m = 1
Results
E = 0.01, 0.5, 0.7, 1
The transmission dependence on deformation for different energies
Transmission value doesn’t depend significantly on energy
The transmission dependence on deformation if we rotate only the centre of the nanotube
The secondary channels don’t influence significantly the value of transmission
m = 0
m = -1
m = 1
Conclusions Transmission doesn’t depend significantly on energy Transmission decreases when the nanotube length
increases For the main channel, transmission decreases sharply
when deformation (magnetic field) increases For the main channel, transmission depends only on
the total deformation For the secondary channel (electrons with positive m),
transmission decreases when deformation increases
Possible applications
Using nanotubes we can assemble an electronical device that works based on magnetic field. The signal decreases sharply when magnetic field is applied.
The results we obtained can be applied to make a sensor similar to Coulomb Balance. The value of force can be measured by the current variation.