Session A3: New Developments in Strontium Ruthenates
8:00 AM–11:00 AM, Monday, March 15, 2010
Room: Oregon Ballroom 203
Sponsoring Unit:
DCMP
Chair: Victor Yakovenko, University of Maryland
Abstract ID: BAPS.2010.MAR.A3.2
Abstract: A3.00002 : Nematic order in Sr$_3$Ru$_2$O$_7$ and triplet superconductivity in Sr$_2$RuO$_4$
8:36 AM–9:12 AM
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Abstract 
Author:
Srinivas Raghu
(Stanford University)
In an externally applied magnetic field, ultra-pure crystals of the bilayer ruthenate compound Sr$_3$Ru$_2$O$_7$ undergo a metamagnetic transition at a temperature which can be tuned towards zero as a function of the angle between B and the crystalline c-axis. This ``metamagnetic quantum critical point", however, is enveloped by a nematic fluid phase with order one resistive anisotropy in the ab plane. In this talk, I will discuss the microscopic origins of metamagnetism and the accompanying nematic order in this system. I propose that both can be understood within the framework of an orbital-ordering tendency of the material and present a phase diagram which accounts for much of the experimentally observed phenomena. By contrast, the closely related monolayer compound, Sr$_2$RuO$_4$, is a spin-triplet superconductor; it does not exhibit metamagnetism or nematic order. This drastic difference in the physical properties of the two materials - despite their structural similarity - points towards a possible microscopic mechanism of triplet superconductivity in Sr$_2$RuO$_4$. I will conclude the talk with a discussion of our recent progress in understanding the microscopic origins of superconductivity in Sr$_2$RuO$_4$.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.A3.2