Sr$_2$Cu(PO$_4$)$_2$: A real material realization of the 1D nearest neighbor Heisenberg chain

TL;DR

This paper demonstrates that Sr$_2$Cu(PO$_4$)$_2$ is an almost perfect 1D spin-1/2 antiferromagnetic Heisenberg chain, combining theoretical calculations and experimental data to establish its ideal magnetic properties for studying quantum spin chains.

Contribution

The study provides comprehensive theoretical and experimental evidence that Sr$_2$Cu(PO$_4$)$_2$ closely realizes the 1D Heisenberg model with nearest neighbor interactions, enabling exploration of beyond-infinite chain effects.

Findings

Sr$_2$Cu(PO$_4$)$_2$ exhibits near-perfect 1D magnetic behavior.

Bethe's solution is applicable due to the material's short-range interactions.

Impurities and defects are analyzed as extrinsic effects.

Abstract

We present evidence that crystalline Sr_2Cu(PO_4)_2 is a nearly perfect one-dimensional (1D) spin-1/2 anti-ferromagnetic Heisenberg model (AHM) chain compound with nearest neighbor only exchange. We undertake a broad theoretical study of the magnetic properties of this compound using first principles (LDA, LDA+U calculations), exact diagonalization and Bethe-ansatz methodologies to decompose the individual magnetic contributions, quantify their effect, and fit to experimental data. We calculate that the conditions of one-dimensionality and short-ranged magnetic interactions are sufficiently fulfilled that Bethe's analytical solution should be applicable, opening up the possibility to explore effects beyond the infinite chain limit of the AHM Hamiltonian. We begin such an exploration by examining some extrinsic effects such as impurities and defects.