Edge states and ballistic transport in zigzag graphene ribbons: The role of SiC polytypes

被引：13

作者：

Miettinen, A. L. ^{[1
]}

Nevius, M. S. ^{[1
]}

Ko, W. ^{[2
]}

Kolmer, M. ^{[2
]}

Li, A-P ^{[2
]}

Nair, M. N. ^{[3
]}

Kierren, B. ^{[4
]}

Moreau, L. ^{[4
]}

Conrad, E. H. ^{[1
]}

Tejeda, A. ^{[3
,5
]}

机构：

[1] Georgia Inst Technol, Atlanta, GA 30332 USA

[2] Oak Ridge Natl Lab, Ctr Nanophase Mat Sci, POB 2009, Oak Ridge, TN 37831 USA

[3] Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France

[4] Univ Lorraine, CNRS, Inst Jean Lamour, F-54506 Vandoeuvre Les Nancy, France

[5] Univ Paris Sud, Lab Phys Solides, CNRS, UMR 8502, F-91405 Orsay, France

来源：

PHYSICAL REVIEW B | 2019年 / 100卷 / 04期

基金：

美国国家科学基金会;

关键词：

NANORIBBONS; GRAPHITE; GROWTH;

D O I：

10.1103/PhysRevB.100.045425

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Zigzag-edge graphene sidewall ribbons grown on 6H-SiC {11 (2) over barn} facet walls are ballistic conductors. It is assumed that graphene sidewall ribbons grown on 4H-SiC {11 (2) over barn} facets would also be ballistic. In this work, we show that SiC polytype indeed matters: ballistic sidewall graphene ribbons only grow on 6H-SiC facets. 4H and 4H-passivated sidewall graphene ribbons are diffusive conductors. Detailed photoemission and microscopy studies show that 6H-SiC sidewall zigzag ribbons are metallic with a pair of n-doped edge states associated with asymmetric edge terminations. In contrast, 4H-SiC zigzag ribbons are strongly bonded to the SiC, severely distorting the ribbon's pi bands. H-2 passivation of the 4H ribbons returns them to a metallic state but they show no evidence of edge states in their photoemission-derived band structure.

引用

页数：8