Abstract

We study the energy levels of fermions in a circular graphene quantum dot subjected to a magnetic field outside the dot, an Aharonov-Bohm magnetic flux inside the dot, and an energy gap (mass term) inside the dot. By solving the Dirac equation in the two regions and matching eigenspinors at the boundary, we obtain the dependence of the energy spectrum on angular momentum, dot radius, magnetic field, energy gap, and flux. The analysis shows that low magnetic fields produce degeneracy that diminishes as the field increases, that magnetic flux opens and enlarges the energy gap without breaking symmetry, and that the mass term widens the band gap while introducing new levels and breaking energy symmetry.

Abstract

We study the energy levels of fermions in a circular graphene quantum dot subjected to a magnetic field outside the dot, an Aharonov-Bohm magnetic flux inside the dot, and an energy gap (mass term) inside the dot. By solving the Dirac equation in the two regions and matching eigenspinors at the boundary, we obtain the dependence of the energy spectrum on angular momentum, dot radius, magnetic field, energy gap, and flux. The analysis shows that low magnetic fields produce degeneracy that diminishes as the field increases, that magnetic flux opens and enlarges the energy gap without breaking symmetry, and that the mass term widens the band gap while introducing new levels and breaking energy symmetry.

Abstract

We study the energy levels of fermions in a circular graphene quantum dot subjected to a magnetic field outside the dot, an Aharonov-Bohm magnetic flux inside the dot, and an energy gap (mass term) inside the dot. By solving the Dirac equation in the two regions and matching eigenspinors at the boundary, we obtain the dependence of the energy spectrum on angular momentum, dot radius, magnetic field, energy gap, and flux. The analysis shows that low magnetic fields produce degeneracy that diminishes as the field increases, that magnetic flux opens and enlarges the energy gap without breaking symmetry, and that the mass term widens the band gap while introducing new levels and breaking energy symmetry.

Abstract

We study the energy levels of fermions in a circular graphene quantum dot subjected to a magnetic field outside the dot, an Aharonov-Bohm magnetic flux inside the dot, and an energy gap (mass term) inside the dot. By solving the Dirac equation in the two regions and matching eigenspinors at the boundary, we obtain the dependence of the energy spectrum on angular momentum, dot radius, magnetic field, energy gap, and flux. The analysis shows that low magnetic fields produce degeneracy that diminishes as the field increases, that magnetic flux opens and enlarges the energy gap without breaking symmetry, and that the mass term widens the band gap while introducing new levels and breaking energy symmetry.