Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 71: Transport: Majorana Fermions (organized by TT)
TT 71.1: Vortrag
Mittwoch, 2. April 2014, 15:00–15:15, HSZ 03
Majorana spin liquid and dimensional reduction in Cs2CuCl4 — •Tim Herfurth, Simon Streib, and Peter Kopietz — Institut für Theoretische Physik, Universität Frankfurt, Max-von-Laue Strasse 1, 60438 Frankfurt, Germany
The low-temperature behavior of the
magnetic insulator Cs2CuCl4
can be modeled by an anisotropic triangular lattice
spin 1/2 Heisenberg antiferromagnet with two different exchange couplings
J and J′ ≈ J/3 .
We show that in a wide range of magnetic fields
the experimentally observed field dependence
of the crossover temperature Tc for
spin-liquid behavior can be explained within a mean-field theory
based on the representation of spin operators
in terms of Majorana fermions.
We also show that for small magnetic fields
the specific heat and the spin susceptibility both
exhibit a maximum as a function of temperature
at Tc = J/2.
In the spin-liquid regime, the Majorana fermions can only propagate along the
direction of the strongest bond, in agreement with
the dimensional reduction scenario advanced by
Balents[1].
Nature 464, 199 (2010)