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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.

Abstract
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 (http://creativecommons.org/licenses/by/4.0/). [http://dx.doi.org/10.1063/1.4966237]

Reference:
The Journal of Chemical Physics 146.9 (2017)

Credits:
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

Microscope:
RHK Big G High-Field Magnet SPM

Fig. 2. STM topography image of carbon-induced islands intercalated between MoS₂ layers and Current-voltage (I(V)) spectroscopy curves recorded on top of an island and on the surrounding MoS₂ layer. The same characteristic I(V) behavior is measured, which unequivocally demonstrates that the island is intercalated and is covered with the same material as the surroundings, i.e., MoS₂. The I(V) curves appear to be metallic, since the set point used in order to record them is within the band gap of MoS₂. The set points are 0.2 nA, 0.5 V

Abstract
Direct growth of flat micrometer-sized bilayer graphene islands in between molybdenum disulfide sheets is achieved by chemical vapor deposition of ethylene at about 800 _C. The temperature assisted decom- position of ethylene takes place mainly at molybdenum disulfide step edges. The carbon atoms interca- late at this high temperature, and during the deposition process, through defects of the molybdenum disulfide surface such as steps and wrinkles. Post growth atomic force microscopy images reveal that cir- cular flat graphene islands have grown at a high yield. They consist of two graphene layers stacked on top of each other with a total thickness of 0.74 nm. Our results demonstrate direct, simple and high yield growth of graphene/molybdenum disulfide heterostructures, which can be of high importance in future nanoelectronic and optoelectronic applications.

2017 Elsevier Inc. All rights reserved.

Reference:
Journal of Colloid and Interface Science 505 (2017): 776-782.

Credits:
Wojciech Kwieciñski^a,b, Kai Sotthewes^a, Bene Poelsema^a, Harold J.W. Zandvliet^a, Pantelis Bampoulis^a,c

^aPhysics of Interfaces and Nanomaterials, MESA+Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
^bFaculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland
^cPhysics of Fluids and J.M. Burgers Centre for Fluid Mechanics, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands

Microscope:
UHV Beetle AFM/STM