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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.
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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 ***Bogoliubov Laboratory of Theoretical Physics, JINR, Dubna
Carbon nanostructures Nanotubes Graphene Graphene pillars
Nanotubes properties Nanotubes 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 nanotubes The 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:
Rotational deformation α Rotational deformation is equivalent to magnetic field
Results Transmission in function of rotational deformation: T(α) Metallic channel m = 0 L=10 , 5, 2, 1 Secondary channel m = 1 L = 0.05, 0.5, 1, 2
Results The transmission dependence on deformation for different energies E = 0.01, 0.5, 0.7, 1 Transmission value doesn’t depend significantly on energy m = 0 The transmission dependence on deformation if we rotate only the centre of the nanotube m = -1 The secondary channels don’t influence significantly the value of transmission m = 1
Conclusions • Transmission doesn’t depend significantly on energy • Transmission decreases when the nanotubelength 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 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. Using nanotubes we can assemble an electronical device that works based on magnetic field. The signal decreases sharply when magnetic field is applied.