Accueil > Français > Événements > Séminaires > Séminaires Magnétisme et Supraconductivité > Archives 2008

Theoretical models of spontaneous time-reversal symmetry breaking in Sr2RuO4 and in underdoped cuprates : p+ip superconductivity and d+id density wave

Victor Yakovenko - Department of Physics, University of Maryland, USA


 

In the recent tour-de-force experiments [1], the group of Kapitulnik at Stanford observed spontaneous time-reversal symmetry breaking in Sr2RuO4 and in underdoped cuprates by measuring the optical polar Kerr effect. In this talk, I discuss theoretical challenges [2] for a theoretical calculation of the polar Kerr angle for Sr2RuO4 in the px+ipy superconducting state, which represents the Cooper pairing with a non-zero angular momentum Lz=1. Then, I present a scenario of the chiral dxy+idx2-y2 density wave [3], which we proposed to explain the time-reversal symmetry breaking in underdoped YBCO. This state describes staggered electron currents circulating around the plaquettes of a square lattice, with the symmetry between the plaquettes broken in a checkerboard manner.

 

[1] J. Xia et al., PRL 97, 167002 (2006) ; 100, 127002 (2008).

[2] V.M. Yakovenko, PRL 98, 087003 (2007) ; R. M. Lutchyn, P. Nagornykh, and V.M. Yakovenko, PRB 77, 144516 (2008) ; in progress.

[3] S. Tewari, C. Zhang, V.M. Yakovenko, and S. Das Sarma, PRL 100, 217004 (2008) ; arXiv:0803.3220.

 

Affiche pdf