Seminar by Tokuro Shimokawa (Osaka University): Thermal and ground-state properties of the Spin-1/2 random-bond Heisenberg antiferromagnet on the kagome lattice

Date

Thursday, April 21, 2016 - 13:30 to 14:30

Location

C016, Lab1

Description

Seminar

 

  • Speaker: Tokuro Shimokawa, Kawamura Group, Osaka University
  • Date: Thursday, April 21st
  • Time: 13:30-14:30
  • Venue: C016, Lab1
  • Title: Thermal and ground-state properties of the Spin-1/2 random-bond Heisenberg antiferromagnet on the kagome lattice
  • Abstract:
Recent theoretical study has suggested that the random S=1/2 Heisenberg antifferomagnet on the triangular lattice might exhibit a randomness-induced quantum spin liquid (QSL) behavior and that this "random singlet (RS) state" might be relevant to the QSL behaviors experimentally observed in triangular organic salts k-(ET)2Cu2(CN)3 and EtMe3Sb[Pd(dmit2)2] [1].
 
Inspired by the theoretical suggestion, we investigate the effect of the quenched bond-randomness on the S=1/2 AF Heisenberg model on the kagome lattice by mean of the exact diagonalization and thermal pure quantum state methods[2].  When the strength of the randomness exceeds a critical value, this kagome model also exhibits the randomness-induced QSL behavior including the T-linear low-temperature specific heat, the gapless susceptibility with a Curie-like component[3]. The dynamical spin structure factor and magnetization curve in the randomness-relevant QSL state[4] agree with the recent experimental data [5][6] on a single-crystal herbertsmithite which is known as a promising candidate of the possible QSL state.
 
[1] K. Watanabe, H. Kawamura, H. Nakano, and T. Sakai, J. Phys. Soc. Jpn. 83, 034714 (2014).
[2] S. Sugiura and A. Shimizu, Phys. Rev. Lett. 111, 010401 (2013).
[3] H. Kawamura, K. Watanabe, and T. S, J. Phys. Soc. Jpn. 83, 103704 (2014).
[4] T. S, K. Watanabe, and H. Kawamura, Phys. Rev. B 92, 134407 (2015).
[5] T.-H. Han, J. S. Helton, S. Chu, D. G. Nocera, J. A. Rodriguez-Rivera, C. Broholm, and Y. S. Lee, Nature 492, 406 (2012).
[6] T.-H. Han, R. Chisnell, C. J. Bonnoit, D. E. Freedman, V. S. Zapf, N. Harrison, D. G. Nocera, Y. Takano, and Y. S. Lee, arXiv:1402.2693.

 

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