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arXiv · 1903.05185

Edge states and ballistic transport in zig-zag graphene ribbons: the role of SiC polytypes

A. L. Miettinen·M. S. Nevius·W. Ko·M. Kolmer·A. -P Li·M. N. Nair·A. Taleb-Ibrahimi·B. Kierren·L. Moreau·E. H. Conrad·A. Tejeda
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Abstract

Zig-zag edge graphene ribbons grown on 6H-SiC facets are ballistic conductors. It has been assumed that zig-zag graphene ribbons grown on 4H-SiC would also be ballistic. However, in this work we show that SiC polytype matters; ballistic graphene ribbons only grow on 6H SiC. 4H and 4H-passivated ribbons are diffusive conductors. Detailed photoemmision and microscopy studies show that 6H-SiC sidewalls zig-zag ribbons are metallic with a pair of n-doped edge states associated with asymmetric edge terminations, In contrast, 4H-SiC zig-zag ribbons are strongly bonded to the SiC; severely distorting the ribbon's $π$-bands. $\text{H}_2$-passivation of the 4H ribbons returns them to a metallic state but show no evidence of edge states.

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A. L. Miettinen, M. S. Nevius, W. Ko, M. Kolmer, A. -P Li, M. N. Nair, A. Taleb-Ibrahimi, B. Kierren, L. Moreau, E. H. Conrad, A. Tejeda. 2019-03-12. Edge states and ballistic transport in zig-zag graphene ribbons: the role of SiC polytypes. https://doi.org/10.1103/physrevb.100.045425

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