Hidden and antiferromagnetic order as a rank-5 superspin in URu2Si2
Abstract
We propose a candidate for the hidden order in URu2Si2: a rank-5 E type spin-density wave between uranium 5f crystal-field doublets Γ7(1) and Γ7(2), breaking time-reversal and lattice tetragonal symmetry in a manner consistent with recent torque measurements [Okazaki , ScienceSCIEAS0036-807510.1126/science.1197358 331, 439 (2011)]. We argue that coupling of this order parameter to magnetic probes can be hidden by crystal-field effects, while still having significant effects on transport, thermodynamics, and magnetic susceptibilities. In a simple tight-binding model for the heavy quasiparticles, we show the connection between the hidden order and antiferromagnetic phases arises since they form different components of this single rank-5 pseudospin vector. Using a phenomenological theory, we show that the experimental pressure-temperature phase diagram can be qualitatively reproduced by tuning terms which break pseudospin rotational symmetry. As a test of our proposal, we predict the presence of small magnetic moments in the basal plane oriented in the [110] direction ordered at the wave vector (0,0,1).
- Publication:
-
Physical Review B
- Pub Date:
- June 2012
- DOI:
- 10.1103/PhysRevB.85.245112
- arXiv:
- arXiv:1203.1047
- Bibcode:
- 2012PhRvB..85x5112R
- Keywords:
-
- 71.27.+a;
- 75.30.Mb;
- Strongly correlated electron systems;
- heavy fermions;
- Valence fluctuation Kondo lattice and heavy-fermion phenomena;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 5 pages