Controllable suppression of the unconventional superconductivity in bulk and thin-film Sr2RuO4 via high-energy electron irradiation

In bulk <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>Sr</a:mi><a:mn>2</a:mn></a:msub><a:msub><a:mi>RuO</a:mi><a:mn>4</a:mn></a:msub></a:mrow></a:math>, the strong sensitivity of the superconducting transition temperature <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mi>T</b:mi><b:mtext>c</b:mtext></b:msub></b:math> to nonmagnetic impurities provides robust evidence for a superconducting order parameter that changes sign around the Fermi surface. In superconducting epitaxial thin-film <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:msub><c:mi>Sr</c:mi><c:mn>2</c:mn></c:msub><c:msub><c:mi>RuO</c:mi><c:mn>4</c:mn></c:msub></c:mrow></c:math>, the relationship between <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:msub><d:mi>T</d:mi><d:mtext>c</d:mtext></d:msub></d:math> and the residual resistivity <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:msub><e:mi>ρ</e:mi><e:mn>0</e:mn></e:msub></e:math>, which in bulk samples is taken to be a proxy for the low-temperature elastic scattering rate, is far less clear. Using high-energy electron irradiation to controllably introduce point disorder into bulk single-crystal and thin-film <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:msub><f:mi>Sr</f:mi><f:mn>2</f:mn></f:msub><f:msub><f:mi>RuO</f:mi><f:mn>4</f:mn></f:msub></f:mrow></f:math>, we show that <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:msub><g:mi>T</g:mi><g:mtext>c</g:mtext></g:msub></g:math> is suppressed in both systems at nearly identical rates. This suggests that part of <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"><h:msub><h:mi>ρ</h:mi><h:mn>0</h:mn></h:msub></h:math> in films comes from defects that do not contribute to superconducting pairbreaking and establishes a quantitative link between the superconductivity of bulk and thin-film samples.