Systematic study of the hidden order in URu$_{2}$Si$_{2}$ as a multipolar order; the role of triakontadipoles.
by
Lars Nordström(Uppsala University)
→
Europe/Stockholm
Nordita West
Nordita West
Description
A systematic search for possible order parameters of the so-called hidden order of URu$_{2}$Si$_{2}$ in terms of multipole tensors is presented. Among the possible candidates that do fulfill the experimental symmetry restrictions on the hidden order parameter, we find one candidate that stand out -- one of the components of a triakontadipole multipole tensor that belongs to the $A_{1u}$ irreducible representation of the point group $D_{4h}$. This solution is characterized by a $\vec{Q}=(0,0,1)$ ordering of the triakontadipoles and has a symmetry that forbids magnetic moments as well as most other multipole ordering on the uranium sites.
This hidden order phase is closely related to the the antiferromagnetic phase, which is manifested in the similarities of the geometries of the calculated Fermi surfaces.
