Conductivity map from scanning tunneling potentiometry

Hao Zhang (1) , Xianqi Li (1) , Yunmei Chen (1) , Corentin Durand (2) , An-Ping Li (2) , X.-G. Zhang (3)

1 UF|Math - Department of Mathematics [Gainesville]
2 CNMS - Center for Nanophase Materials Sciences [Oak Ridge]
3 UF|Physics - Department of Physics [Gainesville]

We present a novel method for extracting two-dimensional (2D) conductivity profiles from large electrochemical potential datasets acquired by scanning tunneling potentiometry of a 2D conductor. The method consists of a data preprocessing procedure to reduce/eliminate noise and a numerical conductivity reconstruction. The preprocessing procedure employs an inverse consistent image registration method to align the forward and backward scans of the same line for each image line followed by a total variation (TV) based image restoration method to obtain a (nearly) noise-free potential from the aligned scans. The preprocessed potential is then used for numerical conductivity reconstruction, based on a TV model solved by accelerated alternating direction method of multiplier. The method is demonstrated on a measurement of the grain boundary of a monolayer graphene, yielding a nearly 10:1 ratio for the grain boundary resistivity over bulk resistivity.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Physique [physics]

Hao Zhang, Xianqi Li, Yunmei Chen, Corentin Durand, An-Ping Li, et al.. Conductivity map from scanning tunneling potentiometry. Review of Scientific Instruments, 2016, 87 (8), pp.083702. ⟨10.1063/1.4960081⟩. ⟨hal-01816706⟩