Chirality-induced spin selectivity

5 problems

• Do enantiomers adsorb differently on oppositely magnetized surfaces

  Contested

  Experiments report that left-handed and right-handed versions of a molecule stick at different rates to a magnet depending on which way it points. If true, magnets could sort mirror-image molecules.

• Mechanism of enantiomer-selective adsorption on magnetized surfaces

  Open

  If mirror-image molecules really stick differently to a magnet depending on its direction, some interaction between the molecule's handedness and the electron spins in the magnet must cause it. Which interaction does so is not known.

• Why chiral molecules polarize electron spins so strongly

  Contested

  Measured spin polarizations through chiral molecules reach tens of percent. The relativistic effect that links spin to motion, spin-orbit coupling, is only a few milli-electronvolts (a tiny energy) in carbon, which predicts effects hundreds of times smaller.

• Size of spin polarization in photoinduced electron transfer across chiral bridges

  Open

  Light can make an electron jump from one part of a molecule to another through a chiral connecting piece. Magnetic resonance measurements can then read the spins of the two resulting charged fragments, which gives a clean test of the effect inside a single molecule.

• Minimal ingredient for CISS magnetoresistance in two-terminal junctions

  Open

  Symmetry theorems say that in the simplest setup, with one entrance, one exit, low voltage and no energy loss along the way, a molecule cannot produce the measured spin signal. Experiments still see a signal, so something must break the assumptions of these theorems.