Quantum rings with tunnel barriers in a threading magnetic field: Spectra, persistent current and ballistic conductance

2009 ◽  
Vol 41 (8) ◽  
pp. 1393-1402 ◽  
Author(s):  
S. Bellucci ◽  
P. Onorato
Keyword(s):  
Magnetic Field ◽  
Persistent Current ◽  
Quantum Rings ◽  
Ballistic Conductance ◽  
Tunnel Barriers

Modulation of persistent current in graphene quantum rings

2021 ◽  
Author(s):  
Francisco Ronan Viana Araújo ◽  
Diego Rabelo da Costa ◽  
André Jorge Carvalho Chaves ◽  
Francisco Etan Batista de Sousa ◽  
Joao Milton Pereira Jr.
Keyword(s):  
Magnetic Field ◽  
Energy Spectrum ◽  
Long Range ◽  
Charge Carriers ◽  
Persistent Current ◽  
Localized States ◽  
Perpendicular Magnetic Field ◽  
Quantum Rings ◽  
Additional Phase

Abstract We investigate the effect of long-range impurity potentials on the persistent current of graphene quantum rings in the presence of an uniform perpendicular magnetic field. The impurity potentials are modeled as finite regions of the ring with a definite length. We show that, due to the relativistic and massless character of the charge carriers in graphene, the effect of such non-uniform potentials on the energy spectrum and on the persistent current of the rings can be reliably modeled by assuming a non-perturbed ring and including an additional phase due to the interaction of the charge carriers with the potential. In addition, the results show the presence of localized states in the impurity regions. Moreover, we show that for the case of a potential created by a p-n-p junction, the persistent current can be modulated by controlling the voltage at the junction.

TRANSPARENCY OF NARROW CONSTRICTIONS IN A GRAPHENE SINGLE ELECTRON TRANSISTOR

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2647-2654 ◽  
Author(s):  
C. STAMPFER ◽  
E. SCHURTENBERGER ◽  
F. MOLITOR ◽  
J. GÜTTINGER ◽  
T. IHN ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Drain Current ◽  
Single Electron ◽  
Single Electron Transistor ◽  
Perpendicular Magnetic Field ◽  
Current Saturation ◽  
Tunnel Barriers ◽  
Graphene Island ◽  
Charging Energy

We report on electronic transport experiments on a graphene single electron transistor as function of a perpendicular magnetic field. The device, which consists of a graphene island connected to source and drain electrodes via two narrow graphene constrictions is electronically characterized and the device exhibits a characteristic charging energy of approx. 3.5 meV. We investigate the homogeneity of the two graphene "tunnel" barriers connecting the single electron transistor to source and drain contacts as function of laterally applied electric fields, which are also used to electrostatically tune the overall device. Further, we focus on the barrier transparency as function of an applied perpendicular magnetic field and we find an increase of transparency for increasing magnetic field and a source-drain current saturation for magnetic fields exceeding 5 T.

scholarly journals Design for a Persistent Current Switch Controlled by Alternating Current Magnetic Field

2018 ◽  
Vol 28 (4) ◽  
pp. 1-5 ◽  
Author(s):  
Chao Li ◽  
Jianzhao Geng ◽  
Jamie Gawith ◽  
Boyang Shen ◽  
Xiuchang Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Alternating Current ◽  
Persistent Current ◽  
Current Switch ◽  
Current Magnetic Field

scholarly journals Circulating persistent current and induced magnetic field in a fractal network

2016 ◽  
Vol 380 (20) ◽  
pp. 1741-1749 ◽  
Author(s):  
Srilekha Saha ◽  
Santanu K. Maiti ◽  
S.N. Karmakar
Keyword(s):  
Magnetic Field ◽  
Persistent Current ◽  
Induced Magnetic Field ◽  
Fractal Network

Magnetic-field-induced electron transitions in concentric double quantum rings

2010 ◽  
Vol 7 (11-12) ◽  
pp. 2608-2611 ◽  
Author(s):  
José Maria Escartin ◽  
Francesc Malet ◽  
Marti Pi ◽  
Manuel Barranco
Keyword(s):  
Magnetic Field ◽  
Double Quantum ◽  
Quantum Rings ◽  
Electron Transitions

scholarly journals Effect of confinement potential shape on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot at finite temperature

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
K. Luhluh Jahan ◽  
Bahadir Boyacioglu ◽  
Ashok Chatterjee
Keyword(s):  
Magnetic Field ◽  
Heat Capacity ◽  
Quantum Dot ◽  
Transport Properties ◽  
Average Energy ◽  
Persistent Current ◽  
Confinement Potential ◽  
Potential Shape ◽  
Gaas Quantum Dot ◽  
The Magnetic Field

Abstract The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot is studied using the power-exponential potential model with steepness parameter p. The average energy, heat capacity, magnetic susceptibility and persistent current are calculated using the canonical ensemble approach at low temperature. It is shown that for soft confinement, the average energy depends strongly on p while it is almost independent of p for hard confinement. The heat capacity is found to be independent of the shape and depth of the confinement potential at low temperatures and for the magnetic field considered. It is shown that the system undergoes a paramagnetic-diamagnetic transition at a critical value of the magnetic field. It is furthermore shown that for low values of the potential depth, the system is always diamagnetic irrespective of the shape of the potential if the magnetic field exceeds a certain value. For a range of the magnetic field, there exists a window of p values in which a re-entrant behavior into the diamagnetic phase can occur. Finally, it is shown that the persistent current in the present quantum dot is diamagnetic in nature and its magnitude increases with the depth of the dot potential but is independent of p for the parameters considered.

Magnetic Field Stability of a Small YBCO Magnet in Persistent Current Mode

2009 ◽  
Vol 19 (3) ◽  
pp. 2194-2197 ◽  
Author(s):  
Woo-Seok Kim ◽  
Chan Park ◽  
Sang Ho Park ◽  
Jikwang Lee ◽  
Jung-Bin Song ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Current Mode ◽  
Persistent Current
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