Theory of Ca$_{10}$Cr$_7$O$_{28}$ as a bilayer breathing-kagome magnet: Classical thermodynamics and semi-classical dynamics

التفاصيل البيبلوغرافية
العنوان: Theory of Ca$_{10}$Cr$_7$O$_{28}$ as a bilayer breathing-kagome magnet: Classical thermodynamics and semi-classical dynamics
المؤلفون: Pohle, Rico, Yan, Han, Shannon, Nic
المصدر: Phys. Rev. B 104, 024426 (2021)
سنة النشر: 2021
المجموعة: Condensed Matter
مصطلحات موضوعية: Condensed Matter - Strongly Correlated Electrons
الوصف: Ca$_{10}$Cr$_7$O$_{28}$ is a novel spin-$1/2$ magnet exhibiting spin liquid behaviour which sets it apart from any previously studied model or material. However, understanding Ca$_{10}$Cr$_7$O$_{28}$ presents a significant challenge, because the low symmetry of the crystal structure leads to very complex interactions, with up to seven inequivalent coupling parameters in the unit cell. Here we explore the origin of the spin-liquid behaviour in Ca$_{10}$Cr$_7$O$_{28}$, starting from the simplest microscopic model consistent with experiment - a Heisenberg model on a single bilayer of the breathing-kagome (BBK) lattice. We use a combination of classical Monte Carlo (MC) simulation and (semi-)classical Molecular Dynamics (MD) simulation to explore the thermodynamic and dynamic properties of this model, and compare these with experimental results for Ca$_{10}$Cr$_7$O$_{28}$. We uncover qualitatively different behaviours on different timescales, and argue that the ground state of Ca$_{10}$Cr$_7$O$_{28}$ is born out of a slowly-fluctuating "spiral spin liquid", while faster fluctuations echo the U(1) spin liquid found in the kagome antiferromagnet. We also identify key differences between longitudinal and transverse spin excitations in applied magnetic field, and argue that these are a distinguishing feature of the spin liquid in the BBK model.
Comment: 32 pages, 22 figures; two animation videos as supplementary files, see https://www.youtube.com/watch?v=GGug4w4MiKQ and https://www.youtube.com/watch?v=jSRF7MZTiNM
نوع الوثيقة: Working Paper
DOI: 10.1103/PhysRevB.104.024426
URL الوصول: http://arxiv.org/abs/2103.08790
رقم الأكسشن: edsarx.2103.08790
قاعدة البيانات: arXiv
الوصف
DOI:10.1103/PhysRevB.104.024426