Fig. 3: Topological defect.
From: Mott resistive switching initiated by topological defects
a Detail of the XLD-PEEM image shown in Fig. 2a in the region where the metallic filament is formed upon the application of a current above the threshold Ith. b Schematic of the monoclinic domains crossing at 60∘ and forming a topological defect. Blue, red and yellow areas identify the three possible monoclinic domains corresponding to the three equivalent order parameter directions \({\hat{{{{\boldsymbol{\epsilon }}}}}}_{n}\). The order parameter at the boundaries between different domains is oriented along \({\hat{{{{\boldsymbol{\epsilon }}}}}}_{1}+{\hat{{{{\boldsymbol{\epsilon }}}}}}_{2}\) (2π/3) for the red-blue interface and along \({\hat{{{{\boldsymbol{\epsilon }}}}}}_{2}+{\hat{{{{\boldsymbol{\epsilon }}}}}}_{3}\) (4π/3) for the blue-yellow interface. The mixed red-yellow triangular region indicates the local suppression of the strain at the topological defect. The energy functionals shown on the left and right, illustrate how a topological defect (green plot, solid line) decreases the insulator-metal energy difference, Δ.
