TY - JOUR

T1 - Charge-Ordered α-Helical Polypeptide Monolayers on Au(111)

AU - Ha, Nguyen T.N.

AU - Sharma, A.

AU - Slawig, Diana

AU - Yochelis, S.

AU - Paltiel, Y.

AU - Zahn, D. R.T.

AU - Salvan, G.

AU - Tegenkamp, Christoph

N1 - Funding Information: We gratefully acknowledge the financial support from the VW Foundation (VWZN3161). A.S. and G.S. acknowledge the financial support provided by the Deutsche Forschungsgemeinschaft (DFG) under the project number 282193534. We thank Olav Hellwig (TU Chemnitz) for providing substrates for the adsorption experiments.

PY - 2020/3/12

Y1 - 2020/3/12

N2 - The growth and electronic levels of molecular monolayer structures of helical polyalanine-based peptides (PA) on Au(111) surfaces were investigated by scanning tunneling microscopy (STM), spectroscopy (STS), and optical ellipsometry under ambient conditions. The self-assembled monolayer (SAM) films revealed a high degree of lateral and rotational order. Moreover, because of the formation of Au-S bonds, resulting from the termination of the helix by cysteine, the PA molecules are oriented, and their intrinsic dipole moment is tilted by around 50° with respect to the surface normal. This charge ordering within the SAM facilitates internal electric fields of up to 1 V/nm, which may renormalize the molecular orbital energies along the helix, thus enabling a high conductance through these peptides. The characteristic bonding scheme and ordering, found in this study for chiral and polar PA molecules, will be important to understand the accompanied spin polarization of propagating electrons as well as the spin exchange mechanism at the hybrid interface.

AB - The growth and electronic levels of molecular monolayer structures of helical polyalanine-based peptides (PA) on Au(111) surfaces were investigated by scanning tunneling microscopy (STM), spectroscopy (STS), and optical ellipsometry under ambient conditions. The self-assembled monolayer (SAM) films revealed a high degree of lateral and rotational order. Moreover, because of the formation of Au-S bonds, resulting from the termination of the helix by cysteine, the PA molecules are oriented, and their intrinsic dipole moment is tilted by around 50° with respect to the surface normal. This charge ordering within the SAM facilitates internal electric fields of up to 1 V/nm, which may renormalize the molecular orbital energies along the helix, thus enabling a high conductance through these peptides. The characteristic bonding scheme and ordering, found in this study for chiral and polar PA molecules, will be important to understand the accompanied spin polarization of propagating electrons as well as the spin exchange mechanism at the hybrid interface.

UR - http://www.scopus.com/inward/record.url?scp=85082387437&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.0c00246

DO - 10.1021/acs.jpcc.0c00246

M3 - Article

AN - SCOPUS:85082387437

VL - 124

SP - 5734

EP - 5739

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 10

ER -