کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8154675 1524802 2016 29 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermodynamic properties of the 2D frustrated Heisenberg model for the entire J1-J2 circle
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
Thermodynamic properties of the 2D frustrated Heisenberg model for the entire J1-J2 circle
چکیده انگلیسی
Using the spherically symmetric self-consistent Green's function method, we consider thermodynamic properties of the S=1/2J1-J2 Heisenberg model on the 2D square lattice. We calculate the temperature dependence of the spin-spin correlation functions cr=〈S0zSrz〉, the gaps in the spin excitation spectrum, the energy E and the heat capacity CV for the whole J1-J2-circle, i.e. for arbitrary φ, J1=cos(φ), J2=sin(φ). Due to low dimension there is no long-range order at T≠0, but the short-range holds the memory of the parent zero-temperature ordered phase (antiferromagnetic, stripe or ferromagnetic). E(φ) and CV(φ) demonstrate extrema “above” the long-range ordered phases and in the regions of rapid short-range rearranging. Tracts of cr(φ) lines have several nodes leading to nonmonotonic cr(T) dependence. For any fixed φ the heat capacity CV(T) always has maximum, tending to zero at T→0, in the narrow vicinity of φ=155° it exhibits an additional frustration-induced low-temperature maximum. We have also found the nonmonotonic behaviour of the spin gaps at φ=270°±0 and exponentially small antiferromagnetic gap up to (T≲0.5) for φ≳270°.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetism and Magnetic Materials - Volume 419, 1 December 2016, Pages 131-139
نویسندگان
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