arXiv subjects

Zeev Vager

Publications and source records attributed to Zeev Vager.

4 recordsLinked to original sources

arXiv2026

Large CISS Polarization from the Hierarchy Between Transport and Geometrical Spin Currents

Large spin polarization observed in chiral-induced spin selectivity (CISS) remains difficult to explain quantitatively. Experimental polarizations measured in chiral molecular systems are often substantially larger than expected from weak microscopic spin-orbit interaction in organic materials. We revisit the geometrical spin current introduced previously for electrons constrained to curved paths and propose a scale argument relevant to transport through double-stranded DNA (dsDNA). Estimation of the intrinsic geometrical spin-current scale using representative dsDNA parameters yields current magnitudes substantially larger than measured transport currents in many CISS experiments. We suggest that this hierarchy allows transport to be interpreted as weak leakage from underlying curved spin-current states. Within this picture, large CISS polarization emerges as transport selection of pre-existing spin-current branches.

physics.chem-ph↗

arXiv2014

A direct way to observe absolute molecular handedness

Unique labeling of chiral stereo-centers must include their handedness. The conventional method that has been developed to do this was originated by three chemists: R.S. Cahn, C. Ingold, and V. Prelog (CIP) and is formally known as R,S nomenclature. It requires knowledge of the spatial absolute configuration of that center. Traditionally, experimental methods of extracting handedness go through the absolute configuration and only then through the application of the CIP convention. Here we show that a direct experimental method of determination of the natural handedness by the polarization of tunneling electrons is almost always compatible with the CIP convention. By the sole use of symmetry arguments we show that the chiral molecule symmetry withdraws the need of fine structure splitting. As a consequence, the polarization of electrons tunneling through the molecular electric dipole direction uniquely determines their handedness. The symmetry breaking argument that induces lack of fine-structure splitting eliminates the need for a precise value of the spin-orbit interaction.

physics.chem-ph↗

arXiv2008

Vortex contribution to equilibrium currents

Like orbitals in atoms and molecules, persistent currents may appear in larger aggregates. Though classically, equilibrium magnetic moment of non-rotating objects is forbidden, it is known that equilibrium quantum circulating currents are allowed. Such currents were predicted to be periodic with the external magnetic field. It is shown that in general, whenever a periodic component is found, there must be a large aperiodic component forcing aperiodic contribution to the equilibrium magnetic moment as a function of the external field.

cond-mat.supr-con↗

arXiv2007

Temporary behavior of 'persistent' current in normal rings

In equilibrium, the number of conduction electrons in a solid substance depends on the conformation of the atoms in the substance. When a magnetic field is applied, it takes time for the system to come to a new equilibrium with a new conformation. During such times, current may flow. But, unless superconduction is involved, the new equilibrium contains no current. It is shown that the transitory currents are consistent with experiments involving magnetization of small rings at low temperatures.

cond-mat.str-el↗