Gapless and gapped spin liquids in Heisenberg models

Date

Sep 1, 2014

Time

4:30 PM - 5:30 PM

Speaker

Federico Becca

Affiliation

SISSA - International School for Advanced Studies, Trieste

Series

MPI-PKS Kolloquium

Language

en

Main Topic

Physik

Other Topics

Physik

Host

qsd14-Workshop

Description

We present our recent numerical calculations on the Heisenberg model on the square and Kagome lattices, showing that gapless spin liquids may be stabilized in highly-frustrated regimes. For the Kagome lattice, we find that a gapless U(1) spin liquid with Dirac cones is competitive with previously proposed gapped spin liquids when only the nearest-neighbor antiferromagnetic interaction is present.[1,2] The inclusion of a next-nearest-neighbor term lead to a Z_2 gapped spin liquid,[3] in agreement with density-matrix renormalization group calculations.[4] In the Heisenberg model on the square lattice with both nearest- and next-nearest-neighbor interactions, a Z_2 spin liquid with gapless spinon excitations is stabilized in the frustrated regime.[5] In all these cases, the magnetically disordered phases can be described by considering Abrikosov fermions coupled to gauge fields. [1] Y. Iqbal, F. Becca, S. Sorella, and D. Poilblanc, Phys. Rev. B 87, 060405(R) (2013). [2] Y. Iqbal, D. Poilblanc, and F. Becca, Phys. Rev. B 89, 020407(R) (2014). [3] W.-J. Hu, Y. Iqbal, F. Becca, D. Poilblanc, and D. Sheng, unpublished. [4] H.-C. Jiang, Z. Wang, and L. Balents, Nat. Phys. 8, 902 (2012). S. Yan, D. Huse, and S. White, Science 332, 1173 (2011). [5] W.-J. Hu, F. Becca, A. Parola, and S. Sorella, Phys. Rev. B 88, 060402(R) (2013).

Last modified: Sep 1, 2014, 9:38:00 AM