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July 2017

Structure dependent spin selectivity in electron transport through oligopeptides

FIG. 3. Averaged I-V data obtained for (A) Al7 and (B) Al5 monolayers recorded under various tip loading forces. Solid and open circles represent the data obtained when the tip is magnetized with positive (H+) and negative (H−) magnetic fields (±1 T), respectively. (C) Variations of spin polarization (P) measured at 1 V as a function of the loading force of Al5 (red) and Al7 (blue) monolayers.

The chiral-induced spin selectivity (CISS) effect entails spin-selective electron transmission through chiral molecules. In the present study, the spin filtering ability of chiral, helical oligopeptide monolayers of two different lengths is demonstrated using magnetic conductive probe atomic force microscopy. Spin-specific nanoscale electron transport studies elucidate that the spin polar- ization is higher for 14-mer oligopeptides than that of the 10-mer. We also show that the spin filtering ability can be tuned by changing the tip-loading force applied on the molecules. The spin selectivity decreases with increasing applied force, an effect attributed to the increased ratio of radius to pitch of the helix upon compression and increased tilt angles between the molecular axis and the surface normal. The method applied here provides new insights into the parameters controlling the CISS effect. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license ( []

The Journal of Chemical Physics 146.9 (2017)

Vankayala Kiran1, Sidney R. Cohen2, and Ron Naaman1

1Department of Chemical Physics, Weizmann Institute of Science, Rehovot NA 76100, Israel
2Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel

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