Lecturer: Dr. Karen Michaeli Affiliation: Weizmann Institute of Science Abstract: The functionality of many biological systems depends on reliable electron transfer with minimal heating. Unlike man-made electric circuits, nature realizes electron transport via insulating chiral molecules. Electron transfer in cells occurs via tunneling---direct or in several steps---through organic molecules, most of which exhibit a helical structure. The high efficiency of electron transfer in these systems, especially over distances of nanometers and beyond, is unexpected for tunneling-based transport and is one of the most compelling questions in the field. Recent experiments have revealed that transport through such helix-shaped molecules strongly depend on the electron's spin. Theoretical attempts to explain this effect rely on large spin-orbit coupling, which is uncommon in organic materials. In this talk I will show that the helical geometry induces correlations between the spin of the transferred electrons and their flow direction. In the tunneling regime, these connections can explain the large spin polarization measured in experiments over an energy range of hundreds of meV, as well as the enhanced transmission through chiral molecules. The directionality generated by the locking of the electron spin and momentum may hold the key to understanding the extremely low dissipation of electric transfer through organic molecules despite strong molecular vibrations. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/condensed?hceid=b...