Exploring thermal properties of an artificial quasicrystal spin-ice system with Penrose tiling

Abstract

Artificial spin-ice systems offer a versatile platform for exploring frustrated magnetism. Among them, the quasicrystal spin-ice system with Penrose tiling exhibits intriguing properties and convoluted spin configurations as a result of the aperiodic nature of its geometry. Due to the complex frustration behavior, the system's physical characteristics, including thermal properties, are challenging to intuitively understand, and remain unexplored. In this study, the thermal properties of the system across the entire temperature range are thoroughly investigated using various numerical approaches. We start with the ground state of this system, which is characterized by two different parts: the long-range-ordered rigid skeleton and the topologically induced emergent frustration parts. We investigate how the physical quantities (e.g., entropy, heat capacity) and spin configuration evolve throughout the entire thermalization process. At low temperatures, Schottky anomalies arise due to excitations within the frustrated spin clusters. At higher temperatures, we quantitatively analyze how the rigid skeleton breaks down under thermal fluctuations, and subsequently observe the emergence of fragmented spin clusters. Our discovery of the various excited states in the systems shows that multiple distinct magnetic states can be accessed within the system. Furthermore, the complex temperature-dependent behavior suggests the possibility of emergent phenomena in artificial quasicrystal spin-ice systems.