Schnack Jürgen, Schulenburg Jörg, Honecker Andreas, Richter Johannes
Fakultät für Physik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany.
Universitätsrechenzentrum, Universität Magdeburg, D-39016 Magdeburg, Germany.
Phys Rev Lett. 2020 Sep 11;125(11):117207. doi: 10.1103/PhysRevLett.125.117207.
We present numerical evidence for the crystallization of magnons below the saturation field at nonzero temperatures for the highly frustrated spin-half kagome Heisenberg antiferromagnet. This phenomenon can be traced back to the existence of independent localized magnons or, equivalently, flatband multimagnon states. We present a loop-gas description of these localized magnons and a phase diagram of this transition, thus providing information for which magnetic fields and temperatures magnon crystallization can be observed experimentally. The emergence of a finite-temperature continuous transition to a magnon crystal is expected to be generic for spin models in dimension D>1 where flatband multimagnon ground states break translational symmetry.
我们给出了在非零温度下，高度受挫的自旋为半整数的 Kagome 海森堡反铁磁体中，低于饱和场时磁振子结晶的数值证据。这种现象可追溯到独立局域磁振子的存在，或者等效地，平带多磁振子态的存在。我们给出了这些局域磁振子的环气体描述以及该转变的相图，从而为在哪些磁场和温度下可以通过实验观察到磁振子结晶提供了信息。对于维度 D>1 中平带多磁振子基态破坏平移对称性的自旋模型，预计会出现到磁振子晶体的有限温度连续转变。
