English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The zero-temperature phase diagram of the spin-$\frac{1}{2}$$J_{1}$--$J_{2}$--$J_{1}^{\perp}$ model on an $AA$-stacked square-latticebilayer is studied using the coupled cluster method implemented to very highorders. Both nearest-neighbor (NN) and frustrating next-nearest-neighborHeisenberg exchange interactions, of strengths $J_{1}>0$ and $J_{2} \equiv\kappa J_{1}>0$, respectively, are included in each layer. The two layers arecoupled via a NN interlayer Heisenberg exchange interaction with a strength$J_{1}^{\perp} \equiv \delta J_{1}$. The magnetic order parameter $M$ (viz.,the sublattice magnetization) is calculated directly in the thermodynamic(infinite-lattice) limit for the two cases when both layers haveantiferromagnetic ordering of either the N\'{e}el or the striped kind, and withthe layers coupled so that NN spins between them are either parallel (when$\delta < 0$) or antiparallel (when $\delta > 0$) to one another. Calculationsare performed at $n$th order in a well-defined sequence of approximations,which exactly preserve both the Goldstone linked cluster theorem and theHellmann-Feynman theorem, with $n \leq 10$. The sole approximation made is toextrapolate such sequences of $n$th-order results for $M$ to the exact limit,$n \to \infty$. By thus locating the points where $M$ vanishes, we calculatethe full phase boundaries of the two collinear AFM phases in the$\kappa$--$\delta$ half-plane with $\kappa > 0$. In particular, we provide theaccurate estimate, ($\kappa \approx 0.547,\delta \approx -0.45$), for theposition of the quantum triple point (QTP) in the region $\delta < 0$. We alsoshow that there is no counterpart of such a QTP in the region $\delta > 0$,where the two quasiclassical phase boundaries show instead an ``avoidedcrossing'' behavior, such that the entire region that contains the nonclassicalparamagnetic phases is singly connected.

physical review. b./physical review. b

Frustrated spin-$\frac{1}{2}$ Heisenberg magnet on a square-lattice  bilayer: High-order study of the quantum critical behavior of the  $J_{1}$--$J_{2}$--$J_{1}^{\perp}$ model