# Robust antiferromagnetic spin waves across the metal-insulator transition in hole-doped BaMn$_{2}$As$_{2}$

## TL;DR

This study investigates how hole doping affects the spin wave dynamics in BaMn₂As₂, revealing that the antiferromagnetic spin waves remain robust across the metal-insulator transition with minimal changes in exchange interactions.

## Contribution

It provides experimental evidence that hole doping causes only minor modifications to the spin dynamics and exchange energies in BaMn₂As₂, highlighting the robustness of antiferromagnetic spin waves.

## Key findings

- Minor suppression of Néel temperature with doping
- Weak interaction of doped holes with Mn spins
- Robust antiferromagnetic spin waves across transition

## Abstract

BaMn$_{2}$As$_{2}$ is an antiferromagnetic insulator where a metal-insulator transition occurs with hole doping via the substitution of Ba with K. The metal-insulator transition causes only a small suppression of the N\'eel temperature ($T_\mathrm{N}$) and the ordered moment, suggesting that doped holes interact weakly with the Mn spin system. Powder inelastic neutron scattering measurements were performed on three different powder samples of Ba$_{1-x}$K$_{x}$Mn$_{2}$As$_{2}$ with $x=$0, 0.125 and 0.25 to study the effect of hole doping and metallization on the spin dynamics of these compounds. We compare the neutron intensities to a linear spin wave theory approximation to the $J_{1}-J_{2}-J_{c}$ Heisenberg model. Hole doping is found to introduce only minor modifications to the exchange energies and spin gap. The changes observed in the exchange constants are consistent with the small drop of $T_\mathrm{N}$ with doping.