Journal Article

FZJ-2015-02785

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Random Strain Fluctuations as Dominant Disorder Source for High-Quality On-Substrate Graphene Devices

Couto, N. J.  G. ; Costanzo, D. ; Engels, S.FZJ* ; Ki, D.-K. ; Watanabe, K. ; Taniguchi, T. ; Stampfer, C.FZJ* ; Guinea, F. ; Morpurgo, A. F. (Corresponding Author)

2014
APS College Park, Md.

This record in other databases:    

Please use a persistent id in citations: http://hdl.handle.net/2128/8549  doi:10.1103/PhysRevX.4.041019

Abstract: We perform systematic investigations of transport through graphene on hexagonal boron nitride (hBN) substrates, together with confocal Raman measurements and a targeted theoretical analysis, to identify the dominant source of disorder in this system. Low-temperature transport measurements on many devices reveal a clear correlation between the carrier mobility μ and the width n of the resistance peak around charge neutrality, demonstrating that charge scattering and density inhomogeneities originate from the same microscopic mechanism. The study of weak localization unambiguously shows that this mechanism is associated with a long-ranged disorder potential and provides clear indications that random pseudomagnetic fields due to strain are the dominant scattering source. Spatially resolved Raman spectroscopy measurements confirm the role of local strain fluctuations, since the linewidth of the Raman 2D peak—containing information of local strain fluctuations present in graphene—correlates with the value of maximum observed mobility. The importance of strain is corroborated by a theoretical analysis of the relation between μ and n that shows how local strain fluctuations reproduce the experimental data at a quantitative level, with n being determined by the scalar deformation potential and μ by the random pseudomagnetic field (consistently with the conclusion drawn from the analysis of weak localization). Throughout our study, we compare the behavior of devices on hBN substrates to that of devices on SiO2 and SrTiO3, and find that all conclusions drawn for the case of hBN are compatible with the observations made on these other materials. These observations suggest that random strain fluctuations are the dominant source of disorder for high-quality graphene on many different substrates, and not only on hexagonal boron nitride.

---

Contributing Institute(s):

1. Halbleiter-Nanoelektronik (PGI-9)
2. JARA-FIT (JARA-FIT)

Research Program(s):

1. 421 - Frontiers of charge based Electronics (POF2-421) (POF2-421)

Appears in the scientific report 2014

---

Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; IF >= 5 ; JCR ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

---