Cation Dependence of the Electronic States in Molecular Triangular Lattice System {\beta}'-X[Pd(dmit)_2]_2: A First-principles study

TL;DR

This study uses first-principles calculations to analyze how different cations influence the electronic states in a series of molecular triangular lattice conductors, revealing systematic variations in transfer integrals and wavefunction distributions.

Contribution

It provides a detailed first-principles analysis of cation-dependent electronic structures in {eta}'-X[Pd(dmit)_2]_2, highlighting systematic anisotropy and wavefunction differences.

Findings

Transfer integrals vary systematically with cation type.

Largest transfer integral along face-to-face stacking direction.

Wavefunction distribution differs between ligands near the Fermi level.

Abstract

The electronic structure of an isostructural series of molecular conductors, {\beta}'-X[Pd(dmit)_2]_2 is systematically studied by a first-principles method based on the density-functional theory. The calculated band structures are fitted to the tight-binding model based on Pd(dmit)_2 dimers on the triangular lattice. We find systematic variation in the anisotropy of the transfer integrals along the three directions of the triangular lattice taking different values. The transfer integral along the face-to-face stacking direction of Pd(dmit)_2 dimers is always the largest. Around the quantum spin liquid, X = EtMe_3Sb, the other two transfer integrals become comparable. We also report sensible differences in the distribution of wavefunctions near the Fermi level between the two dmit ligands of the Pd(dmit)_2 molecule.