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Title
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Electrical dipole on gapped graphene : bound states and atomic collapse
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Author
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Abstract
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| We investigate the energy spectrum, wave functions, and local density of states of an electrical dipole placed on a sheet of gapped graphene as function of the charge strength Z alpha for different sizes of the dipole and for different regularization parameters. The dipole is modeled as consisting of a positive and negative charge. Bound states are found within the gap region with some energy levels that anticross and others that cross as function of the impurity strength Z alpha. The anticrossings are more pronounced and move to higher charges Z alpha when the length of the dipole decreases. These energy levels turn into atomic collapse states when they enter the positive (or negative) energy continuum. A smooth transition from the single-impurity behavior to the dipole one is observed: The states diving towards the continuum in the single-impurity case are gradually replaced by a series of anticrossings that represent a continuation of the diving states in the single-impurity case. By studying the local density of states at the edge of the dipole we show how the series of anticrossings persist in the positive and negative continuum. |
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Language
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English
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Source (journal)
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Physical review B / American Physical Society. - New York, N.Y, 2016, currens
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Publication
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New York, N.Y
:
American Physical Society
,
2018
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ISSN
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2469-9969
[online]
2469-9950
[print]
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DOI
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10.1103/PHYSREVB.98.165420
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Volume/pages
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98
:16
(2018)
, 10 p.
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Article Reference
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165420
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ISI
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000447302700010
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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