Bandwidth-disorder phase diagram of half doped layered manganites

TL;DR

This paper maps the phase diagram of half-doped layered manganites, revealing how reduced dimensionality influences charge-orbital order and disorder phenomena relevant to colossal magnetoresistance.

Contribution

It establishes the intrinsic bandwidth-disorder phase diagram for 2D layered manganites, extending previous 3D studies and analyzing the effects of reduced dimensionality.

Findings

Reduced dimensionality impacts charge-orbital order-disorder phenomena.

The phase diagram differs from 3D manganites, highlighting 2D effects.

Insights into the mother state of colossal magnetoresistance in layered manganites.

Abstract

Phase diagrams in the plane of $r_A$ (the average ionic radius, related to one-electron bandwidth $W$) and $\sigma^2$ (the ionic radius variance, measuring the quenched disorder), or ``bandwidth-disorder phase diagrams'', have been established for perovskite manganites, with three-dimensional (3$D$) Mn-O network. Here we establish the intrinsic bandwidth-disorder phase diagram of half-doped layered manganites with the two-dimensional (2$D$) Mn-O network, examining in detail the ``mother state'' of the colossal magnetoresistance (CMR) phenomenon in crystals without ferromagnetic instability. The consequences of the reduced dimensionality, from 3$D$ to 2$D$, on the order-disorder phenomena in the charge-orbital sectors are also highlighted.