First-principles prediction of a decagonal quasicrystal containing boron

TL;DR

This paper predicts a metastable decagonal quasicrystal containing boron using first-principles calculations, revealing a phase transition driven by tile fluctuations and suggesting potential high-temperature stability.

Contribution

It introduces a first-principles approach to predict a boron-containing decagonal quasicrystal and analyzes its stability and phase transition behavior.

Findings

Decagonal quasicrystal B$_{38}$Mg$_{17}$Ru$_{45}$ is metastable at low temperatures.

A phase transition from crystalline to tile-fluctuating state is predicted at higher temperatures.

Many tilings are energetically close to stability, indicating potential for thermodynamic stability.

Abstract

We interpret experimentally known B-Mg-Ru crystals as quasicrystal approximants. These approximant structures imply a deterministic decoration of tiles by atoms that can be extended quasiperiodically. Experimentally observed structural disorder corresponds to phason (tile flip) fluctuations. First-principles total energy calculations reveal that many distinct tilings lie close to stability at low temperatures. Transfer matrix calculations based on these energies suggest a phase transition from a crystalline state at low temperatures to a high temperature state characterized by tile fluctuations. We predict B$_{38}$Mg$_{17}$Ru$_{45}$ forms a decagonal quasicrystal that is metastable at low temperatures and may be thermodynamically stable at high temperatures.