Electronic correlation and geometrical frustration in molecular solids: A systematic ab initio study of β′−X[Pd(dmit)2]2

Takahiro Misawa,Kazuyoshi Yoshimi,Takao Tsumuraya

doi:10.1103/physrevresearch.2.032072

Takahiro Misawa, Kazuyoshi Yoshimi + Show 1 more

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https://doi.org/10.1103/physrevresearch.2.032072

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Abstract

We systematically derive low-energy effective Hamiltonians for molecular solids $\beta^\prime$-$X$[Pd(dmit)$_{2}$]$_{2}$ ($X$ represents a cation) using ab initio density functional theory calculations and clarify how the cation controls the inter-dimer transfer integrals and the interaction parameters. The effective models are solved using the exact diagonalization method and the antiferromagnetic ordered moment is shown to be significantly suppressed around the spin-liquid candidate of $X$=EtMe$_{3}$Sb, which is reported in experiments. We also show that both the geometrical frustration and the off-site interactions play essential roles in the suppression of antiferromagnetic ordering. This systematic derivation and analysis of the low-energy effective Hamiltonians offer a firm basis to clarify the nature of the quantum spin liquid found in $\beta^\prime$-EtMe$_{3}$Sb[Pd(dmit)$_{2}$]$_{2}$.

Highlights

Quantum spin liquids (QSLs) [1], which are Mott insulators without any broken symmetry, even at zero temperature, are new states of matter that have attracted much interest in the last few decades
We have successfully reproduced the overall trend in the magnetic properties by performing comprehensive ab initio calculations for all available β -type Pd(dmit)2 salts
These results indicate that a QSL state without magnetic order appears in EtMe3Sb, which is consistent with previous experimental results

Summary

Rapid Communications

Electronic correlation and geometrical frustration in molecular solids: A systematic ab initio study of β -X [Pd(dmit)2]2. We systematically derive low-energy effective Hamiltonians for molecular solids β -X [Pd(dmit)2]2 (X represents a cation) using ab initio density functional theory calculations and clarify how the cation controls the interdimer transfer integrals and the interaction parameters. The effective models are solved using the exact diagonalization method and the antiferromagnetic ordered moment is shown to be significantly suppressed around the spin-liquid candidate of X = EtMe3Sb, which is reported in experiments. We show that both the geometrical frustration and the off-site interactions play essential roles in the suppression of antiferromagnetic ordering. This systematic derivation and analysis of the low-energy effective Hamiltonians offers a firm basis to clarify the nature of the quantum spin liquid found in β -EtMe3Sb[Pd(dmit)2]2

Introduction

Published by the American Physical Society

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