Dr. Jasper van Wezel
Argonne National Laboratory
Materials Science Division
|TITLE:||"Chirality in Orbital Ordered Charge Density Waves"|
|DATE:||Thursday, June 30, 2011|
|PLACE:||Building 212 / A-157|
Refreshments will be served at 10:45 a.m.
ABSTRACT: It is well known that materials with charge order may spontaneously break inversion symmetry. This effect underlies for example the emergence of ferroelectricity in SnTe and the dramatic hysteresis effects in NbSe3. Only very recently however, has it been realized that this type of charge order may also result in a chiral state . The inversion symmetry is then broken with an axial vector instead of a polar one. In this seminar I will discuss the mechanism by which such chiral charge density waves may be formed, focusing in particular on its realization in the layered material TiSe2. I will show that chirality may be expected to be a generic property of certain types of charge density waves involving orbital order, and point out the prerequisites for their occurrence.