The giant Stark effect in armchair-edge phosphorene nanoribbons under a transverse electric field |
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Authors: | Benliang Zhou Benhu Zhou Pu Liu Guanghui Zhou |
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Affiliation: | 1. Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation, Ministry of Education, and Synergetic Innovation Center for Quantum Effects and Applications of Hunan, Hunan Normal University, Changsha 410081, China;2. Department of Physics, Shaoyang University, Shaoyang 422001, China |
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Abstract: | We study the variation of electronic properties for armchair-edge phosphorene nanoribbons (APNRs) modulated by a transverse electric field. Within the tight-binding model Hamiltonian, and by solving the differential Schrödinger equation, we find that a band gap closure appears at the critical field due to the giant Stark effect for an APNR. The gap closure has no field polarity, and the gap varies quadratically for small fields but becomes linear for larger ones. We attribute the giant Stark effect to the broken edge degeneracy, i.e., the charge redistributions of the conduction band minimum and valence band maximum states localized at opposite edges induced by the field. By combined with the Green's function approach, it is shown that in the presence of the critical field a gap of density of states (DOS) disappears and a high value DOS turns up at the energy position of the band gap closure. Finally, as the field increases, we find the band gap decreases more rapidly and the gap closure occurs at smaller fields for wider ribbons. Both the band gap and DOS variations with the field show an insulator-metal transition induced by a transverse electric field for the APNR. Our results show that wider APNRs are more appreciable to design field-effect transistors. |
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Keywords: | Phosphorene nanoribbons Green's function approach Giant Stark effect Transverse electric field Insulator-metal transition |
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