Dislocations and plasticity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>KTaO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math> perovskite modeled with an interatomic potential

Potassium tantalate <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>KTaO</a:mi><a:mn>3</a:mn></a:msub></a:math> is a cubic, paraelectric perovskite ceramic that exhibits surprising ductility at room temperature as most recently reported. Much like strontium titanate (<b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mi>SrTiO</b:mi><b:mn>3</b:mn></b:msub></b:math>), plastic deformation is accommodated by dislocations gliding in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mo>{</c:mo><c:mn>110</c:mn><c:mo>}</c:mo></c:mrow></c:math> planes. In this work, we propose a new interatomic potential for <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:msub><d:mi>KTaO</d:mi><d:mn>3</d:mn></d:msub></d:math>, and apply it to model dislocations with <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mrow><e:mo>〈</e:mo><e:mn>110</e:mn><e:mo>〉</e:mo></e:mrow></e:math> Burgers vector. We demonstrate that dislocations dissociate, and finely characterize their core structure and Peierls potential. Dislocations of edge character can carry a positive or negative electric charge, but we show that charge-neutral configurations are energetically more favorable. We also perform high-resolution electron microscopy to validate our simulation methodology. Comparing our results with other ductile perovskites, we confirm <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:msub><f:mi>KTaO</f:mi><f:mn>3</f:mn></f:msub></f:math> to be ductile, but stiffer than <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:msub><g:mi>SrTiO</g:mi><g:mn>3</g:mn></g:msub></g:math>.