PIRSA:14050074

Video URL

https://pirsa.org/14050074

Gapless spin liquids in frustrated Heisenberg models

Becca, F. (2014). Gapless spin liquids in frustrated Heisenberg models. Perimeter Institute for Theoretical Physics. https://pirsa.org/14050074

Becca, Federico. Gapless spin liquids in frustrated Heisenberg models. Perimeter Institute for Theoretical Physics, May. 13, 2014, https://pirsa.org/14050074 

          @misc{ scivideos_PIRSA:14050074,
            doi = {10.48660/14050074},
            url = {https://pirsa.org/14050074},
            author = {Becca, Federico},
            keywords = {Quantum Matter},
            language = {en},
            title = {Gapless spin liquids in frustrated Heisenberg models},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2014},
            month = {may},
            note = {PIRSA:14050074 see, \url{https://scivideos.org/index.php/pirsa/14050074}}
          }

Federico Becca SISSA International School for Advanced Studies

Talk numberPIRSA:14050074
DOI10.48660/14050074
Source RepositoryPIRSA
Collection
Talk Type Scientific Series
Subject

Abstract

We present our recent numerical calculations for the Heisenberg model on the square and
Kagome lattices, showing that gapless spin liquids may be stabilized in highly-frustrated
regimes. In particular, we start from Gutzwiller-projected fermionic states that may
describe magnetically disordered phases,[1] and apply few Lanczos steps in order to improve
their accuracy. Thanks to the variance extrapolation technique,[2] accurate estimations of
the energies are possible, for both the ground state and few low-energy excitations.
Our approach suggests that magnetically disordered phases can be described by Abrikosov
fermions coupled to gauge fields.

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.[3,4] The inclusion of a next-nearest-neighbor term
lead to a Z_2 gapped spin liquid,[5] in agreement with density-matrix renormalization group
calculations.[6] 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.[7] This results are (partially) in agreement with recent
density-matrix renormalization group on large cylinders.[8]

[1] X.-G. Wen, Phys. Rev. B {\bf 44}, 2664 (1991); Phys. Rev. B {\bf 65}, 165113 (2002).
[2] S. Sorella, Phys. Rev. B {\bf 64}, 024512 (2001).
[3] Y. Iqbal, F. Becca, S. Sorella, and D. Poilblanc, Phys. Rev. B 87, 060405(R) (2013).
[4] Y. Iqbal, D. Poilblanc, and F. Becca, Phys. Rev. B 89, 020407(R) (2014).
[5] W.-J. Hu, Y. Iqbal, F. Becca, D. Poilblanc, and D. Sheng, unpublished.
[6] H.-C. Jiang, Z. Wang, and L. Balents, Nat. Phys. 8, 902 (2012);
S. Yan, D. Huse, and S. White, Science 332, 1173 (2011).
[7] W.-J. Hu, F. Becca, A. Parola, and S. Sorella, Phys. Rev. B 88, 060402(R) (2013).
[8] S.-S. Gong, W.Z., D.N. Sheng, O.I. Motrunich, and M.P.A. Fisher, arXiv:1311.5962 (2013).