Abstract
The surfaces of rutile transition-metal oxides (TMO2) are widely investigated for catalysis, photoelectrochemical solar cells, memristors, and supercapacitors, but their structures have remained controversial. Here we employ density functional theory to predict that a universal behavior of metallic TMO2 surfaces, i.e., the stoichiometric TMO2 surfaces, exhibit a contrast reversal in simulated scanning tunneling microscopy (STM) images at different scanning biases. The predictions are verified by experimental STM imaging of RuO2(110) surfaces and this feature is shown to enable accurate determinations of the TMO2(110) surface structures under various conditions. This work provides different insights into the electronic properties of TMO2(110) surfaces and offers an effective method to directly map the surface structure and point defects using bias-dependent STM.
Original language | English |
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Article number | 035409 |
Journal | Physical Review B |
Volume | 103 |
Issue number | 3 |
DOIs | |
State | Published - Jan 11 2021 |
Funding
T.F. and S.T.P. acknowledge support by Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, Grant No. DE-FG0209ER46554 and by the McMinn Endowment. T.F. also acknowledges the Professional Development Funding from Oak Ridge National Laboratory. Simulations were performed at the National Energy Research Scientific Computing Center (NERSC), a DOE, Office of Science, User Facility funded through Contract No. DE-AC02-05CH11231. Simulations also used the Extreme Science and Engineering Discovery Environment (XSEDE). Y.W., A.H., M.F.C., T.Z.W., and P.C.S. acknowledge support from the U.S. DOE, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. We also acknowledge fruitful discussions and help from T. Berlijn.