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Updated: Jun 11, 2026

Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
External bias dependent direct to indirect band gap transition in graphene nanoribbon
Kausik Majumdar1, Kota V R M Murali, Navakanta Bhat
1Department of Electrical Communication Engineering and Center of Excellence in Nanoelectronics, Indian Institute of Science, Bangalore 560012, India. kausik@ece.iisc.ernet.in
Abstract:
In this work, using self-consistent tight-binding calculations, for the first time, we show that a direct to indirect band gap transition is possible in an armchair graphene nanoribbon by the application of an external bias along the width of the ribbon, opening up the possibility of new device applications. With the help of the Dirac equation, we qualitatively explain this band gap transition using the asymmetry in the spatial distribution of the perturbation potential produced inside the nanoribbon by the external bias. This is followed by the verification of the band gap trends with a numerical technique using Magnus expansion of matrix exponentials. Finally, we show that the carrier effective masses possess tunable sharp characters in the vicinity of the band gap transition points.
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