Magneto-optical Faraday effect in spin-liquid candidates

We propose an experiment to use the magneto-optical Faraday effect to probe the dynamic Hall conductivity of spin-liquid candidates. Theory predicts that an external magnetic field will generate an internal gauge field. If the source of conductivity is in spinons with a Fermi surface, a finite Farad...

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Bibliographic Details
Main Authors: Drew, H. Dennis, Lee, Patrick A., Colbert, Jacob Reid
Other Authors: Massachusetts Institute of Technology. Department of Physics
Format: Article
Language:English
Published: American Physical Society 2014
Online Access:http://hdl.handle.net/1721.1/89533
https://orcid.org/0000-0002-5883-787X
https://orcid.org/0000-0001-7809-8157
Description
Summary:We propose an experiment to use the magneto-optical Faraday effect to probe the dynamic Hall conductivity of spin-liquid candidates. Theory predicts that an external magnetic field will generate an internal gauge field. If the source of conductivity is in spinons with a Fermi surface, a finite Faraday rotation angle is expected. We predict the angle to scale as the square of the frequency rather than display the standard cyclotron resonance pattern. Furthermore, the Faraday effect should be able to distinguish the ground state of the spin liquid, as we predict no rotation for massless Dirac spinons. We give a semiquantitative estimate for the magnitude of the effect and find that it should be experimentally feasible to detect in both κ-(ET)[subscript 2] Cu[subscript 2] (CN)[subscript 3] and, if the spinons form a Fermi surface, herbertsmithite. We also comment on the magneto-optical Kerr effect and show that the imaginary part of the Kerr angle (circular dichroism) may be measurable.