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Raman Response in Antiferromagnetic Two-Leg S=1/2 Heisenberg Ladders

Kai P. Schmidt·Christian Knetter·Götz S. Uhrig
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Abstract

The Raman response in the antiferromagnetic 2-leg S=1/2 Heisenberg ladder is calculated for various couplings by continuous unitary transformations. For leg couplings above 80% of the rung coupling a characteristic 2-peak structure occurs with a point of zero intensity within the continuum. Experimental data for CaV_2O_5 and La_yCa_(14-y)Cu_24O_41 are analyzed and the coupling constants are determined. Evidence is found that the Heisenberg model is not sufficient to describe cuprate ladders. We argue that a cyclic exchange term is the appropriate extension.

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Kai P. Schmidt, Christian Knetter, Götz S. Uhrig. 2001-07-20. Raman Response in Antiferromagnetic Two-Leg S=1/2 Heisenberg Ladders. https://doi.org/10.1209/epl%2Fi2001-00601-y

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