Electronic Nematicity in Interface Superconducting <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>LAO</mml:mi><mml:mo>/</mml:mo><mml:mi>KTO</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>111</mml:mn><m

The symmetry of superconducting and normal states is at the core of superconductivity research. Emergent electronic nematicity, which spontaneously breaks the rotational symmetry, has been found in the normal state of various types of unconventional superconductors. Here, we exploit the angle-resolved resistivity method to systematically measure the nematicity of the interface superconducting <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>LaAlO</a:mi></a:mrow><a:mn>3</a:mn></a:msub><a:mo>/</a:mo><a:msub><a:mrow><a:mi>KTaO</a:mi></a:mrow><a:mn>3</a:mn></a:msub><a:mo stretchy="false">(</a:mo><a:mn>111</a:mn><a:mo stretchy="false">)</a:mo></a:mrow></a:math> (<e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mi>LAO</e:mi><e:mo>/</e:mo><e:mi>KTO</e:mi></e:mrow></e:math>). Compared to the normal state, electronic nematicity is enhanced substantially by superconducting fluctuations around the superconducting temperature <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:msub><g:mi>T</g:mi><g:mi mathvariant="normal">c</g:mi></g:msub></g:mrow></g:math>. More importantly, <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mrow><j:msub><j:mi>T</j:mi><j:mi mathvariant="normal">c</j:mi></j:msub></j:mrow></j:math> is also anisotropic in plane and angle dependent. The nematicity consists of a dominant <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mrow><m:msub><m:mi mathvariant="normal">C</m:mi><m:mn>2</m:mn></m:msub></m:mrow></m:math> component and a <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:mrow><p:msub><p:mi mathvariant="normal">C</p:mi><p:mn>4</p:mn></p:msub></p:mrow></p:math> component, which can be explained by the presence of nematic domains. After the superconductivity is suppressed by a magnetic field, the uncovered quantum metal state manifests significant nematicity that is contributed by residual nematic superconducting fluctuations. A coherent picture of nematic interface superconductivity can be retrieved from the measured nematicity phase diagram that is crucial for the understanding of quantum metal state, electronic nematicity, and interface superconductivity.