تقرير
Exact Ground States and Phase Diagram of the Quantum Compass Model under an in-plane Field
| العنوان: | Exact Ground States and Phase Diagram of the Quantum Compass Model under an in-plane Field |
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| المؤلفون: | Richards, A. D. S., Sørensen, Erik S. |
| سنة النشر: | 2023 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Strongly Correlated Electrons |
| الوصف: | We consider the square lattice $S$=1/2 quantum compass model (QCM) parameterized by $J_x, J_z$, under a field, $\mathbf{h}$, in the $x$-$z$ plane. At the special field value, $(h_x^\star,h_z^\star)$=$2S(J_x,J_z)$, we show that the QCM Hamiltonian may be written in a form such that two simple product states can be identified as exact ground-states, below a gap. Exact excited states can also be found. The exact product states are characterized by a staggered vector chirality, attaining a non-zero value in the surrounding phase. The resulting gapped phase, which we denote by $SVC$ occupies most of the in-plane field phase diagram. For some values of $h_x>h_z$ and $h_z>h_x$ at the edges of the phase diagram, we have found transitions between the $SVC$ phase and phases of weakly-coupled Ising-chain states, $Z$ and $X$. In zero field, the QCM is known to have an emergent sub-extensive ground-state degeneracy. As the field is increased from zero, we find that this degeneracy is partially lifted, resulting in bond-oriented spin-stripe states, $L$ and $R$, which are each separated from one another and the $SVC$ phase by first-order transitions. Our findings are important for understanding the field dependent phase diagram of materials with predominantly directionally-dependent Ising interactions. Comment: 7 pages, 4 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2310.01384 |
| رقم الأكسشن: | edsarx.2310.01384 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |