Three-dimensional electronic instabilities in polymerized solid A1C60

TL;DR

This paper investigates the electronic and magnetic properties of polymerized A1C60 (A=K, Rb) using first-principles methods, revealing three-dimensional magnetic fluctuations and a semi-metallic spectrum in the low-temperature phase.

Contribution

It provides a detailed first-principles analysis of the electronic structure and magnetic fluctuations in polymerized A1C60, highlighting their three-dimensional nature and magnetic ordering tendencies.

Findings

Magnetic fluctuations favor a 3D antiferromagnetic order.

The phase exhibits a semi-metallic electronic spectrum.

Electronic and magnetic properties are strongly three-dimensional.

Abstract

The low-temperature structure of A1C60 (A=K, Rb) is an ordered array of polymerized C60 chains, with magnetic properties that suggest a non-metallic ground state. We study the paramagnetic state of this phase using first-principles electronic-structure methods, and examine the magnetic fluctuations around this state using a model Hamiltonian. The electronic and magnetic properties of even this polymerized phase remain strongly three dimensional, and the magnetic fluctuations favor an unusual three-dimensional antiferromagnetically ordered structure with a semi-metallic electronic spectrum.