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Novel magnetization plateaus in frustrated quantum magnets

Speaker: 
Prof. Pinaki Sengupta (Nanyang Technological University)
Date: 
Fri, 28/09/2012 - 12:00pm to 1:00pm
Location: 
S13-M01-11 (Physics Conference Room)
Event Type: 
Seminars

Abstract:

Geometrically frustrated spin systems are known to exhibit novel quantum phenomena. One example is the unique non-monotonic field dependence of the magnetization and the associated emergence of magnetization plateuas in a class of frustrated spin compounds commonly known as the Shastry-Sutherland compounds after their underlying magnetic lattice.

In this talk, I shall discuss the mechanism for the formation of these plateaus. In the first half of the talk, I shall compare the quantitative predictions from our recently developed unconstrained Chern-Simons theory with experimental observations in SrCu2(BO3)2. Interestingly, our theoretical calculations predict that at the plateaus, the elementary magnetic excitations, triplons, form well-defined stripes.

Evidence of such stripes have recently been reported in TmB4, another compound belonging to this family. In the second half of the talk, I shall discuss the formation of magnetizaion plateaus in a new family of Shastry-Sutherland compounds, viz., the rare-earth tetraborides. The bare Shastry-Sutherland model needs to be supplemented by additional longer range interactions to describe the magnetic properties of these compounds. I shall discuss he underlying microscopic models and our recent studies of these models.

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