Chirality-Induced Spin Selectivity in a Coarse-Grained Tight-Binding Model for Helicene

Matthias Geyer, Rafael Gutierrez, Vladimiro Mujica, Gianaurelio Cuniberti

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Spin-dependent effects in helical molecular systems, leading to the so-called chirality-induced spin selectivity (CISS) effect, have strongly attracted the attention of the chemical and physical community over the past few years. A large amount of experimental material has been collected so far, and different theoretical approaches have been presented to rationalize the CISS effect. The problem is, however, still a subject of debate. We present a semianalytical coarse-grained atomistic description of the electronic structure of a simple helical molecule, including spin-orbit interactions. For reference, we consider helicene, which is a pure carbon-based helical system with no chiral centers, and which has been previously shown experimentally to display a CISS effect. Our model exploits perturbation theory and a Löwdin-like partitioning to obtain an effective π-πHamiltonian, where all coupling coefficients depend on the helical geometry and predefined Slater-Koster parameters. As a result, they can be explicitly computed, thus providing physically meaningful orders of magnitude. We further discuss the conditions under which a nonvanishing spin polarization can be obtained in the model. We expect that our approach will serve to bridge the gap between purely phenomenological model Hamiltonians and more advanced first-principles methodologies.

Original languageEnglish
JournalJournal of Physical Chemistry C
DOIs
Publication statusAccepted/In press - Jan 1 2019

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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