Concomitant appearance of conductivity and superconductivity in (111) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>LaAlO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow><mml:mo>/</mml:mo><mml:mrow><mml:msub><mml:mi>SrTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> interface with metal capping

In epitaxial polar-oxide interfaces, conductivity sets in beyond a finite number of monolayers (ML). This threshold for is explained by accumulating sufficient electric potential to initiate charge transfer the interface. Here we experimentally and theoretically study ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ (111) interface where critical thickness ${t}_{c}$ nine ${\mathrm{LaAlO}}_{3}$ ML required turn from insulating conducting even superconducting. We show that decreases 3 when depositing cobalt overlayer (capping) 6 platinum capping. The latter result contrasts with (001) interface, capping increases bare Our density functional theory calculations Hubbard U term confirm observed metal-capped interfaces. Interestingly, appears concomitantly superconductivity metal/${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ contrast interfaces without superconductivity. attribute this dissimilarity different orbital polarization ${e}_{g}^{\ensuremath{'}}$ versus ${d}_{xy}$