The hypothesis, nevertheless, that the interplay in between electrical and magnetic fields could explain the choice for one or the other mirror-image type of a particle– so-called enantiomers– emerged early on.It was just a few years earlier, however, that the very first indirect evidence emerged that the various mixes of these force fields can indeed “differentiate” between the 2 mirror images of a particle. If the interplay in between magnetism and electric fields really triggers “enantioselective” effects, then the strength of the interaction in between chiral molecules and magnetic surfaces need to likewise differ, for example– depending on whether a right-handed or left-handed particle “settles” on the surface.Mirror images prefer opposing magnetic fieldsAnd this is indeed the case, as a group of researchers led by Karl-Heinz Ernst from the Empas Surface Science and Coating Technologies lab and colleagues at the Peter Grünberg Institute at the Forschungszentrum Jülich in Germany recently reported in the clinical journal Advanced Materials. They then transferred spiral-shaped chiral molecules– a 1:1 mixture of left- and right-handed heptahelicene molecules– onto these cobalt islands in an ultrahigh vacuum.Then they “just” counted the number of right- and left-handed helicene molecules on the in a different way allured cobalt islands, nearly 800 particles in overall, again using scanning tunneling microscopy. The electric field of a metal surface area (E, pointing upwards, best side) moves the electrons in the bound heptahelical molecules; these accumulate somewhat in the lower part of the particle near the surface. Depending on the handedness of the bound particle, electrons with one direction of spin preferentially flow– or “tunnel”– through the molecule, meaning that electrons with the “wrong” spin are filtered out.This chirality-induced spin selectivity (CISS result, see left side of the graphic) had actually currently been observed in earlier studies, but it stayed uncertain whether an ensemble of molecules is needed for this or whether specific particles also display this effect.
If the interaction between magnetism and electric fields in fact activates “enantioselective” results, then the strength of the interaction between magnetic surfaces and chiral molecules need to likewise vary, for example– depending on whether a left-handed or right-handed particle “settles” on the surface.Mirror images choose opposing magnetic fieldsAnd this is certainly the case, as a team of researchers led by Karl-Heinz Ernst from the Empas Surface Science and Coating Technologies lab and associates at the Peter Grünberg Institute at the Forschungszentrum Jülich in Germany just recently reported in the clinical journal Advanced Materials. They then transferred spiral-shaped chiral particles– a 1:1 mix of left- and right-handed heptahelicene molecules– onto these cobalt islands in an ultrahigh vacuum.Then they “merely” counted the number of right- and left-handed helicene particles on the in a different way magnetized cobalt islands, nearly 800 molecules in overall, again using scanning tunneling microscopy. Depending on the handedness of the bound particle, electrons with one direction of spin preferentially circulation– or “tunnel”– through the particle, meaning that electrons with the “incorrect” spin are filtered out.This chirality-induced spin selectivity (CISS effect, see left side of the graphic) had actually already been observed in earlier studies, but it remained unclear whether an ensemble of particles is necessary for this or whether private particles likewise show this result.