Carrier induced ferromagnetism in the insulating Mn doped III-V semiconductor InP

TL;DR

This paper investigates the unique ferromagnetic properties of Mn-doped InP, revealing that its magnetism is governed by impurity band physics rather than valence band models, aligning well with experimental data.

Contribution

The study combines theoretical approaches to demonstrate that impurity band physics explains ferromagnetism in Mn-doped InP, contrasting with previous valence band assumptions.

Findings

Critical temperatures scale linearly with Mn concentration.

Magnetization curves are unconventional compared to GaMnAs.

Fermi level resides in an impurity band, not the valence band.

Abstract

Although InP and GaAs have very similar band-structure their magnetic properties appear to drastically differ. Critical temperatures in (In,Mn)P are much smaller than that of (Ga,Mn)As and scale linearly with Mn concentration. This is in contrast to the square root behaviour found in (Ga,Mn)As. Moreover the magnetization curve exhibits an unconventional shape in (In,Mn)P contrasting with the conventional one of well annealed (Ga,Mn)As. By combining several theoretical approaches, the nature of ferromagnetism in Mn doped InP is investigated. It appears that the magnetic properties are essentially controlled by the position of the Mn acceptor level. Our calculations are in excellent agreement with recent measurements for both critical temperatures and magnetizations. The results are only consistent with a Fermi level lying in an impurity band, ruling out the possibility to understand the physical properties of Mn doped InP within the valence band scenario. The quantitative success found here reveals a predictive tool of choice that should open interesting pathways to address magnetic properties in other compounds