Abstract
Scanning tunneling microscopy (STM) is one of the indispensable tools to characterize surface structures, but the distinction between atomic geometry and electronic effects based on the measured tunneling current is not always straightforward. In particular, for single-atomic-thick materials (graphene or boron nitride) on metallic substrates, counterintuitive phenomena such as a larger tunneling current for insulators than for metal and a topography opposite to the atomic geometry are reported. Using first-principles density functional theory calculations combined with analytical modeling, we reveal the critical role of penetrating states of metallic substrates that surpass 2D material states, hindering the measurement of intrinsic 2D materials states and leading to topography inversion. Our finding should be instrumental in the interpretation of STM topographies of atomic-thick materials and in the development of 2D material for (opto)electronic and various quantum applications.
Original language | English |
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Article number | 7321 |
Journal | Scientific Reports |
Volume | 12 |
Issue number | 1 |
DOIs | |
State | Published - Dec 2022 |
Funding
The research was supported by the U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Quantum Science Center (M.Y. for DFT modeling) and Office of Basic Energy (M.Y. for analytical modeling); and by the New generation research program at Korea Institute for Advanced Study (KIAS) (C.P.). This research used resources of the Oak Ridge Leadership Computing Facility, the National Energy Research Scientific Computing Center, a U.S. Department of Energy Office of Science User Facilities, and the Center for Advanced Computation of KIAS. We thank J. Park and A.-P. Li to discuss their STM data. The research was supported by the U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Quantum Science Center (M.Y. for DFT modeling) and Office of Basic Energy (M.Y. for analytical modeling); and by the New generation research program at Korea Institute for Advanced Study (KIAS) (C.P.). This research used resources of the Oak Ridge Leadership Computing Facility, the National Energy Research Scientific Computing Center, a U.S. Department of Energy Office of Science User Facilities, and the Center for Advanced Computation of KIAS. We thank J. Park and A.-P. Li to discuss their STM data.