Hard Squares for z = –1

We consider the spin-1/2 antiferromagnetic Heisenberg model on a bilayer honeycomb lattice including interlayer frustration in the presence of an external magnetic field. In the vicinity of the saturation field, we map the low-energy states of this quantum system onto the spatial configurations of hard hexagons on a honeycomb lattice. As a result, we can construct effective classical models (lattice-gas as well as Ising models) on the honeycomb lattice to calculate the properties of the frustrated quantum Heisenberg spin system in the low-temperature regime. We perform classical Monte Carlo simulations for a hard-hexagon model and adopt known results for an Ising model to discuss the finite-temperature order-disorder phase transition that is driven by a magnetic field at low temperatures. We also discuss an effective-model description around the ideal frustration case and find indications for a spin-flop like transition in the considered isotropic spin model.

show abstract

“…., see Ref. 34. In the spin language, this corresponds to the ordering of the localized magnons as their density increases.…”

Section: Hard Hexagons On the Honeycomb Latticementioning

confidence: 96%

“…A more precise value of this constant for hard hexagons on a honeycomb lattice can be found in Ref. 34.…”

Section: Hard Hexagons On the Honeycomb Latticementioning

confidence: 99%

Frustrated honeycomb-lattice bilayer quantum antiferromagnet in a magnetic field: Unconventional phase transitions in a two-dimensional isotropic Heisenberg model

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The continuum limit of each of the gapless sectors is shown to be described by a superconformal field theory with central charge c = 1. 4 The paper is organized as follows. In the remainder of this section, we define the supersymmetric model, discuss the analytic and numerical techniques that we employ and, finally, summarize the results on the ground state degeneracy of the supersymmetric model on the triangular lattice that were established previously.…”

mentioning

confidence: 99%

Supersymmetric lattice fermions on the triangular lattice: superfrustration and criticality

et al. 2012

View full text Add to dashboard Cite

We study a model for itinerant, strongly interacting fermions where a judicious tuning of the interactions leads to a supersymmetric Hamiltonian. On the triangular lattice this model is known to exhibit a property called superfrustration, which is characterized by an extensive ground state entropy. Using a combination of numerical and analytical methods we study various ladder geometries obtained by imposing doubly periodic boundary conditions on the triangular lattice. We compare our results to various bounds on the ground state degeneracy obtained in the literature.For all systems we find that the number of ground states grows exponentially with system size.For two of the models that we study we obtain the exact number of ground states by solving the cohomology problem. For one of these, we find that via a sequence of mappings the entire spectrum can be understood. It exhibits a gapped phase at 1/4 filling and a gapless phase at 1/6 filling and phase separation at intermediate fillings. The gapless phase separates into an exponential number of sectors, where the continuum limit of each sector is described by a superconformal field theory.

show abstract

“…Especially the latter makes Configurational entropy of the √ 3 phase as calculated using the hard-hexagon model, and that of the hard honeycomb model, calculated for the overlayer phase, following Refs. [26,27].…”

Section: Entropic Stabilitymentioning

confidence: 99%

Temperature-dependent structure, elasticity, and entropic stability of Bi phases on Cu{111}

et al. 2014

View full text Add to dashboard Cite

We have used low energy electron microscopy (LEEM) to characterize the structure and stability of Bi phases on Cu{111}. As a function of temperature we find that the Cu{111}(• -Bi surface alloy phase gradually dealloys and is fully depleted from Bi at a temperature of 803 K. The dealloying leads to a defect induced change of its elastic properties. The Bi surface alloy phase coexists with a Bi overlayer phase that exhibits a sharp decrease in density in a narrow temperature interval just below the temperature where the surface alloy phase has fully dealloyed. LEEM is used to directly evaluate the structure as well as the entropic contributions that determine the stability of each of the phases.

show abstract

Hard Squares for z = –1

Cited by 11 publications

References 9 publications

Frustrated honeycomb-lattice bilayer quantum antiferromagnet in a magnetic field: Unconventional phase transitions in a two-dimensional isotropic Heisenberg model

Frustrated honeycomb-lattice bilayer quantum antiferromagnet in a magnetic field: Unconventional phase transitions in a two-dimensional isotropic Heisenberg model

Supersymmetric lattice fermions on the triangular lattice: superfrustration and criticality

Temperature-dependent structure, elasticity, and entropic stability of Bi phases on Cu{111}

Contact Info

Product

Resources

About