AFM‐Based Spin‐Exchange Microscopy Using Chiral Molecules

Abstract

Local magnetic imaging at nanoscale resolution is desirable for basic studies of magnetic materials and for magnetic logic and memories. However, such local imaging is hard to achieve by means of standard magnetic force microscopy. Other techniques require low temperatures, high vacuum, or strict limitations on the sample conditions. A simple and robust method is presented for locally resolved magnetic imaging based on short‐range spin‐exchange interactions that can be scaled down to atomic resolution. The presented method requires a conventional AFM tip functionalized with a chiral molecule. In proximity to the measured magnetic sample, charge redistribution in the chiral molecule leads to a transient spin state, caused by the chiral‐induced spin‐selectivity effect, followed by the exchange interaction with the imaged sample. While magnetic force microscopy imaging strongly depends on a large working distance, an accurate image is achieved using the molecular tip in proximity to the sample. The chiral molecules' spin‐exchange interaction is found to be 150 meV. Using the tip with the adsorbed chiral molecules, two oppositely magnetized samples are characterized, and a magnetic imaging is performed. This method is simple to perform at room temperature and does not require high‐vacuum conditions.

Chirality-driven topological electronic structure of DNA-like materials

“…However, Refs. 6 , 30 , 31 have pointed out that the transient spin polarization is induced by the charge redistribution among the molecule and the substrate, which we call the charge transfer. We state that the charge transfer is already chirality-dependent as the driving force of the chiral selection.…”

Charge Redistribution and Spin Polarization Driven by Correlation Induced Electron Exchange in Chiral Molecules

“…Related to these observations are also the results showing strongly enantiomer dependent binding energies on ferromagnetic metals. 48 − 51 Enantiomer separation was addressed theoretically in ref ( 41 ). For molecules in contact with ferromagnetic metal, the electronic exchange plays a crucial role in the magnetic response.…”

Evidence for new enantiospecific interaction force in chiral biomolecules

“…Consequently, the emergence of these dipoles implies that at each electric pole, there is at least a fraction of an unpaired electron, i.e., spin polarization is intrinsically associated with the electric dipole formation in chiral molecules. The concept of charge polarization accompanied by spin polarization was veri ed in experiments in which the interaction of chiral molecules with ferromagnetic substrates was probed 19,20 .…”