TY - JOUR
T1 - Effects of electron-phonon coupling on quantum interference in polyenes
AU - Tsuji, Yuta
AU - Yoshizawa, Kazunari
N1 - Funding Information:
This work was supported by KAKENHI Grant Nos. JP15K13710, JP17K14440, and JP17H03117 from Japan Society for the Promotion of Science (JSPS) and the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), the MEXT Projects of “Integrated Research Consortium on Chemical Sciences,” “Cooperative Research Program of Network Joint Research Center for Materials and Devices,” “Elements Strategy Initiative to Form Core Research Center,” and JST-CREST “Innovative Catalysts.” The computation was mainly carried out using the computer facilities at Research Institute for Information Technology, Kyushu University. Y.T. thanks JSPS Grant-in-Aid for Scientific Research on Innovative Areas “Discrete Geometric Analysis for Materials Design”: Grant No. 18H04488.
Publisher Copyright:
© 2018 Author(s).
PY - 2018/10/7
Y1 - 2018/10/7
N2 - It has been well accepted that when quantum interference (QI) occurs in a single molecular junction comprised of a π-conjugated molecule, the elastic π-electron transmission is blocked, while the elastic σ-electron transmission remains unchanged. When it comes to inelastic transport, in which passing electrons across the molecule trapped in between two metallic electrodes lose their energy through electron-phonon coupling, it is not necessarily obvious whether vibration affects the QI feature or not. In this paper, on the basis of a Hückel/tight-binding model, we address the inelastic transport through linear and cyclic polyenes which are conditioned to show QI. The zeroth-order Green's function approximated by the negative inverse of the adjacency matrix of a molecular graph is used in conjunction with the lowest order expansion of the self-consistent Born approximation. Owing to the simplification of the model, it just finds the limited applicability for the π-to-π scattering. Only topological aspects of dephasing are included. In such a theoretical construct, the alternant nature of the π-conjugated molecule is found helpful for classifying the dephasing patterns based on the parity of atomic sites. A rule is proposed, and it says that when both starred or both unstarred atoms are connected with the electrodes, QI always occurs, and atoms which belong to a different partite set from that of the atoms connected with the electrodes contribute to the inelastic π-to-π scattering. If QI occurs when a starred atom and an unstarred atom are connected with the electrodes, the contribution of the inelastic π-to-π scattering to the transport is expected to be unimportant.
AB - It has been well accepted that when quantum interference (QI) occurs in a single molecular junction comprised of a π-conjugated molecule, the elastic π-electron transmission is blocked, while the elastic σ-electron transmission remains unchanged. When it comes to inelastic transport, in which passing electrons across the molecule trapped in between two metallic electrodes lose their energy through electron-phonon coupling, it is not necessarily obvious whether vibration affects the QI feature or not. In this paper, on the basis of a Hückel/tight-binding model, we address the inelastic transport through linear and cyclic polyenes which are conditioned to show QI. The zeroth-order Green's function approximated by the negative inverse of the adjacency matrix of a molecular graph is used in conjunction with the lowest order expansion of the self-consistent Born approximation. Owing to the simplification of the model, it just finds the limited applicability for the π-to-π scattering. Only topological aspects of dephasing are included. In such a theoretical construct, the alternant nature of the π-conjugated molecule is found helpful for classifying the dephasing patterns based on the parity of atomic sites. A rule is proposed, and it says that when both starred or both unstarred atoms are connected with the electrodes, QI always occurs, and atoms which belong to a different partite set from that of the atoms connected with the electrodes contribute to the inelastic π-to-π scattering. If QI occurs when a starred atom and an unstarred atom are connected with the electrodes, the contribution of the inelastic π-to-π scattering to the transport is expected to be unimportant.
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U2 - 10.1063/1.5048955
DO - 10.1063/1.5048955
M3 - Article
C2 - 30292216
AN - SCOPUS:85054453930
VL - 149
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 13
M1 - 134115
ER -