Interplay between vibrations and spin polarization in the CISS effect of helical molecules

Giovanni Cuniberti, TUD, Faculty of Mechanical Science & Engineering; Ismael Diez Perez & Lev Kantorovich, King’s, Department of Physics

Research area: Materials sciences & physics

Chirality Induced Spin Selectivity (CISS) has gained much interest in various scientific fields since it has a broad impact in areas such as nanoscale charge transport, spintronics and biochemical reactions. In brief, when an electron circulates along a chiral molecular backbone, the particular helicoidal potential imposed by the chiral structure enhances the scattering of one of the electron spins over the other, resulting in the generation of a spin-polarized current. The experimental observations point at various factors playing an important role in controlling the CISS effect such as the molecular length, the temperature, and the direction of the intrinsic molecular dipole moment, to mention the most relevant ones. In a previously funded joint transCampus project, the group addressed the influence of the intrinsic electrical dipole moment on the resulting spin polarization in helical peptides. With the current proposal, the group around Giovanni Cuniberti and Ismael Diez Perez, now strengthened through the participation of Lev Kantorovich from King’s, aims at extending the experimental and theoretical investigations to address the influence of temperature and of molecular length on the CISS effect.  This will give us further insight for rationalizing the mechanisms of spin selectivity in chiral molecules, and it will open the possibility to elaborate methodologies for designing hybrid electrode/molecule interfaces using chiral molecular systems for room-temperature spintronics applications. The concepts learnt here will further help understanding the role of homochiral motifs recurrently exploited in biological systems in topics such as local magnetic fields affecting enzymatic reactivity and/or the possible role of spin-polarized currents in the long-range electron transfer/transport in biology.