Possible Magnetic Behavior in Oxygen-deficient {\beta}-PtO2

TL;DR

This study uses density functional theory to reveal that oxygen vacancies in beta-PtO2 induce local magnetic moments and influence catalytic properties, with different charge states affecting stability and magnetism.

Contribution

It demonstrates that oxygen vacancies in beta-PtO2 create local magnetic moments and explores their stability and implications for catalysis using advanced computational methods.

Findings

Oxygen vacancies induce local magnetic moments on neighboring atoms.

Charge states of vacancies influence magnetic properties and stability.

Negatively charged vacancies are most stable across a wide band gap range.

Abstract

We studied the electronic properties of beta-platinum dioxide ({\beta}-PtO2), a catalytic material, based on density functional theory. Using the GGA+U method which reproduces the GW band structures and the experimental structural parameters, we found that the creation of an oxygen vacancy will induce local magnetic moment on the neighboring Pt and O atoms. The magnetism originates not only from the unpaired electrons that occupy the vacancy induced gap state, but also from the itinerant valence electrons. Because of antiferromagnetic (AF) coupling and the localized nature of gap states, the total magnetic moment is zero for charge-neutral state (V_o^0) and is ~ 1 \mu B for singly-charged states (V_o^\mu). Calculation of grand potential shows that, the three charge states (V_o^0, V_o^\pm) are of the same stability within a small region, and the negatively charged state (V_o^-) is energetically favored within a wide range of the band gap. On this basis we discussed the implication on catalytic behavior.