Stripe phase of J1-J2 Heisenberg antiferromagnet on bcc lattice: GF method vs Z2xO(3) nonlinear sigma-model

1. Milan Pantić, Univerzitet u Novom Sadu, Prirodno-matematički fakultet, Departman za fiziku, Serbia

Starting from J1-J2 Heisenberg antiferromagnet on body centered cubic lattice we obtain low-temperature effective field theory in terms of Z2xO(3) nonlinear sigma model. We analyze low energy sector of the nls-m and obtain four branches of type A Nambu-Goldstone bosons. Since excitations display instability at J2/ J1 > 2/3, we identify the critical ratio of exchange integrals to be J2/ J1 = 2/3. On the other hand, GF method predicts critical ratio J2/ J1 = 0.7142. By comparing predictions from Z2xO(3) NLs-M with RPA and QMC, we discuss its applicability on low temperature regime of corresponding Heisenberg model.

Ključne reči: Heisenberg antiferromagnet; bcc lattice

Tematska oblast: SIMPOZIJUM A - Nauka materije, kondenzovane materije i fizika čvrstog stanja

Datum: 29.07.2019.

Contemporary Materials 2019 - Savremeni Materijali

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