Molecular orbital concept on spin-flip transport in molecular junctions

Tomofumi Tada, Takahiro Yamamoto, Satoshi Watanabe

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The spin-dependent electron transport correlated with spin-flip dynamics in a molecular junction was investigated in the wave-packet and Green's function approaches. The molecular junction adopted in this work is described by a simple one-dimensional tight-binding chain including a localized spin. The spin exchange coupling J between the localized and conduction electron spins was taken into account through the s-d Hamiltonian. The wave-packet simulations showed that the transmission probabilities in both the spin-flip and no-flip processes show large peaks at the eigenvalues of the spin singlet (-3J/4) and triplet (J/4) states, and that, different transmission properties appear at the mid-gap of the two eigenvalues: the spin-flip process shows a moderate decrease, whereas the no-flip process an abrupt drop. Dividing the s-d Hamiltonian into two submatrices and referring to the molecular orbital concept for the coherent electron transport, we found that the moderate decrease in the spin-flip process at the mid-gap is the result of a coherent-and-cooperative contribution from the singlet and triplet states of the conduction and localized electron spins, and that, the abrupt drop in the no-flip process at the mid-gap is mainly caused by the coherent cancellation from the singlet and triplet states. The molecular orbital concept available for the electron transport including spin-flip scattering processes is described in Green's function method, in analogy to the one derived for the spinless electron transport.

Original languageEnglish
Pages (from-to)775-788
Number of pages14
JournalTheoretical Chemistry Accounts
Volume130
Issue number4-6
DOIs
Publication statusPublished - Dec 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry

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