1 / 16

2007.4.19~20

Monte Carlo Study of the J 1 -J 2 antiferromagnetic XY model on the triangular lattice. Jin-Hong Park and Jung Hoon Han. Department of Physics Sungkyunkwan University. 2007.4.19~20. XY model on triangular lattice. Classical XY model Hamiltonian.

salene
Download Presentation

2007.4.19~20

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Monte Carlo Study of the J1-J2 antiferromagnetic XY model on the triangular lattice Jin-Hong Park and Jung Hoon Han Department of PhysicsSungkyunkwan University 2007.4.19~20

  2. XY model on triangular lattice Classical XY model Hamiltonian . Two types of the transition found on triangular lattice • Kosterlitz-Thouless(KT) transition • Chirality transition

  3. - - - + + + - - - + + + - - - + + + XY model on triangular lattice T Paramagnetic Magnetic T =0.512 TKT =0.501 Chiral The separation of the phase temperatures is extremely small. The chirality-ordered phase is not well-defined. Sooyeul Lee and Koo-Chul Lee, Phys. Rev. B 57, 8472 (1998)

  4. = or Biquadratic interaction on triangular lattice ? If the spin-spin interaction is biquadratic, a spin-nematic order is realized instead. . Biquadratic interaction supports a spin nematic order.

  5. J1-J2XY model We want to study a variant of the XY model in which the chirality order exists over an extended region of the phase diagram by combining quadratic and bi-quadratic interactions T paramagnetic A chiral phase is seen to exist over an extended temperature region when J2/J1 is large chiral, non-magnetic magnetic J2/J1 J2/J1=9 We focus on J2/J1 = 9.

  6. Specific heat J2/J1= 9 (L = 15, 30, 60). Two phase transitions clearly identified T1 T2

  7. Magnetic/nematic parameters Magnetic order parameter Nematic order parameter We study the nature of the phases with the magnetic and nematic order parameters

  8. Chiral order parameter Chiral order parameter 2 4 - + 1 3

  9. Magnetic order

  10. Nematic order Binder cumulent TKT = 0.460

  11. Helicity Modulus Helicity modulus This TKT must agree with the one obtained from Binder cumulent in the previous page. TKT = 0.459 .

  12. Critical phase for nematic order below TKT disorder critical TKT We find critical dependence of N1 and N2 on the lattice dimension L below TKT.

  13. Chiral order Chiral order undergoes two phase transitions. The first one at higher temperature obeys a scaling plot. A scaling plot of chirality using the  = 0.15,  = 0.69, and T= 0.462. This T is higher than TKT of the nematic order.

  14. Phase diagram T J2/J1 =0 Paramagnetic Magnetic T J2/J1 =9 Magnetic Chiral Paramagnetic By introducing frustration in the form of J2 we find an extended region of chiral phase

  15. Summary • We find a clear separation of magnetic (T1) and nematic (T2) phase transition for J2/J1 = 9. • Quite remarkably, the staggered chirality order sets in at T=T2, where • the nematic order occurs. • This is the first demonstration of the clear separation of the chiral phase transition and the magnetic phase transition in XY-like models.

  16. Appendix +1 +1

More Related