Umbrella-coplanar transition in the triangular XXZ model with arbitrary spin
Umbrella-coplanar transition in the triangular XXZ model with arbitrary spin
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DOI：
10.1103/physrevb.93.224402
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发表时间：
2015-10
影响因子：
3.7
通讯作者：
G. Marmorini;D. Yamamoto;I. Danshita
中科院分区：
文献类型：
--
作者：
G. Marmorini;D. Yamamoto;I. Danshita
量子三角XXZ模型最近获得了大量新的理论成果，特别是在${\mathrm{Ba}}_{3}{\mathrm{CoSb}}_{2}{\mathrm{O}}_{9}$化合物的模拟方面。特别是，人们已经理解，在纵向磁场中，伞形(锥形)相在基态相图的所有易平面区中经典地稳定，由于量子涨落的影响而显著减少。通过采用在高场区有效的稀玻色气体展开，我们提供了在自旋为S元的任意值下这一现象的更多定量信息；我们的结果改进了对1元/S元展开的现有估计。我们量化了较高自旋抑制量子涨落效应的程度。此外，我们还展示了在三维分层系统中，相对较小的反铁磁层间耦合如何具有类似的结果，即在相图的某些部分带回伞状相。
The quantum triangular XXZ model has recently enjoyed a wealth of new theoretical results, especially in relation to the modeling of the ${\mathrm{Ba}}_{3}{\mathrm{CoSb}}_{2}{\mathrm{O}}_{9}$ compound. In particular, it has been understood that in a longitudinal magnetic field the umbrella (cone) phase, classically stable in all the easy-plane region of the ground-state phase diagram, is considerably reduced by the effect of quantum fluctuations. We provide more quantitative information for this phenomenon at arbitrary value of the site spin $S$, by employing the dilute Bose gas expansion, valid in the high-field regime; our results improve the available estimates of the $1/S$ expansion. We quantify the extent to which a higher spin suppresses the effect of quantum fluctuations. Besides, we show how in three-dimensional layered systems a relatively small antiferromagnetic interlayer coupling has a similar consequence of bringing back the umbrella phase in some part of the phase diagram.