Ghost transmission: How large basis sets can make electron transport calculations worse
- Northwestern Univ., Evanston, IL (United States)
- Arizona State University, Tempe, AZ (United States)
The Landauer approach has proven to be an invaluable tool for calculating the electron transport properties of single molecules, especially when combined with a nonequilibrium Green’s function approach and Kohn–Sham density functional theory. However, when using large nonorthogonal atom-centered basis sets, such as those common in quantum chemistry, one can find erroneous results if the Landauer approach is applied blindly. In fact, basis sets of triple-zeta quality or higher sometimes result in an artificially high transmission and possibly even qualitatively wrong conclusions regarding chemical trends. In these cases, transport persists when molecular atoms are replaced by basis functions alone (“ghost atoms”). The occurrence of such ghost transmission is correlated with low-energy virtual molecular orbitals of the central subsystem and may be interpreted as a biased and thus inaccurate description of vacuum transmission. An approximate practical correction scheme is to calculate the ghost transmission and subtract it from the full transmission. As a further consequence of this study, it is recommended that sensitive molecules be used for parameter studies, in particular those whose transmission functions show antiresonance features such as benzene-based systems connected to the electrodes in meta positions and other low-conducting systems such as alkanes and silanes.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Bio-Inspired Energy Science (CBES)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Contributing Organization:
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois (United States)
- DOE Contract Number:
- SC0000989
- OSTI ID:
- 1065515
- Journal Information:
- Journal of Chemical Physics, Vol. 132 (2), Issue 2; Related Information: CBES partners with Northwestern University (lead); Harvard University; New York University; Pennsylvania State University; University of Michigan; University of Pittsburgh
- Country of Publication:
- United States
- Language:
- English
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