Encoding Complexity within Supramolecular Analogues of Frustrated Magnets

Abstract

At the heart of systems chemistry lies the idea that supramolecular interactions can give rise to complex and unexpected collective states that emerge on a fundamentally different lengthscale to that of the interactions themselves. While in certain cases - e.g. the self-assembly of virus-like polyhedral cages from coordination building blocks - it is possible to control emergence in a systematic manner, the development of general approaches remains a fundamental challenge in the field. In the conceptually-related domain of frustrated magnetism - where collective states give rise to exotic physics of relevance to data storage and spintronics - the task of predicting emergent behaviour is simplified through control over the geometry and form of the magnetic interactions from which complexity arises. Seeking to combine approaches from these two fields, we study here the solid phases of inorganic polymer chains assembled from non-magnetic gold(I)/silver(I) cations and cyanide anions. We show the periodic inter-chain potential encodes a supramolecular interaction that can be tuned to mimic different magnetic interactions between XY spins ("spin rotors"). Because the chains pack on a triangular lattice, the crystal structures of gold(I)/silver(I) cyanides can be interpreted in terms of the phase behaviour of triangular XY magnets. Complex magnetic states predicted for this family - including hidden quadrupolar order and emergent spin-vortex quasiparticles - are realised for the first time in the structural chemistry of these cyanide polymers. In this way we demonstrate both how simple inorganic materials might behave as structural analogues of otherwise-unrealisable "toy" spin models, and also how a theoretical understanding of those models might be used to predict and control emergent phenomena in chemical systems.

22 pages, 3 figures. Submitted to Nature Chemistry

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• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Helical Metal Inside a Topological Band Insulator
• The quadrupolar phases of the S=1 bilinear-biquadratic Heisenberg model on the triangular lattice
• Quadrupolar correlations and spin freezing in S = 1 triangular lattice antiferromagnets

Cited by in corpus (13)

• Emergent Order in the Kagome Ising Magnet Dy3Mg2Sb3O14
• Competing nematic interactions in a generalized XY model in two and three dimensions
• One-dimensional magnetic order in the metal-organic framework Tb(HCOO)3
• Magnetic quasi-long-range ordering in nematics due to competition between higher-order couplings
• Frustrated ground states of a generalized XY model and their mapping to non-magnetic structural analogues
• $XY$ model with antinematic interaction
• Phase diagrams of antiferromagnetic $XY$ model on a triangular lattice with higher-order interactions
• Multiple phase transitions in the $XY$ model with nematic-like couplings
• Frustrated Ising charge correlations in the kagome metal ScV${}_6$Sn${}_6$
• Noncentrosymmetric Triangular Magnet CaMnTeO${}_6$: Strong Quantum Fluctuations and Role of s0 vs. s2 Electronic States in Competing Exchange Interactions
• Room temperature spin-ice physics in cadmium cyanide
• XY model with competing higher-order interactions
• Generalized $XY$ model with competing antiferromagnetic and antinematic interactions