Crystal Lattice of Ferroelectric Ammonium Sulfate with Tilted Ammonium and Sulfate (IMAGE)
Caption
Top: Crystal lattice of ferroelectric ammonium sulfate [(NH4)2SO4] with tilted ammonium (NH4+ tetrahedra (nitrogen: blue, hydrogen: white) and sulfate (SO42-) tetrahedra (sulfur: yellow, oxygen: red). The green arrow shows the direction of the macroscopic polarization P. Blue arrows: local dipoles between sulphur and oxygen atoms. The electron density maps shown in the bottom left panel and the movie are taken in the plane highlighted in grey. Bottom left: Stationary electron density with a high value on the sulfur (red) and smaller values on the oxygen atoms (yellow). Bottom right: Change of local dipoles at a delay time of 2.8 picoseconds (ps) after excitation of the ammonium sulfate sample. An anisotropic shift of charge reduces the dipole pointing to the right and increases the other 3 dipoles.
Credit
MBI Berlin
Usage Restrictions
The image may only be used with appropriate caption and credit.
License
Licensed content