Probing enhanced superconductivity in van der Waals polytypes of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi mathvariant="normal">V</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>TaS</mml:mi><mml:mn>2<

Layered transition metal dichalcogenides (TMDs) stabilize in multiple structural forms with profoundly distinct and exotic electronic phases. Interfacing different layer types is a promising route to manipulate TMDs' properties, not only as a means to engineer quantum devices but also as a route to explore fundamental physics in complex matter. Here we use angle-resolved photoemission (ARPES) to investigate a strong layering-dependent enhancement of superconductivity in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>TaS</a:mi><a:mn>2</a:mn></a:msub></a:math>, in which the superconducting transition temperature, <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mi>T</b:mi><b:mi>c</b:mi></b:msub></b:math>, of its <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mn>2</c:mn><c:mi>H</c:mi></c:mrow></c:math> structural phase is nearly tripled when insulating <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mrow><d:mn>1</d:mn><d:mi>T</d:mi></d:mrow></d:math> layers are inserted into the system. The study is facilitated by a vanadium-intercalation approach to synthesizing various <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:msub><e:mi>TaS</e:mi><e:mn>2</e:mn></e:msub></e:math> polytypes, which improves the quality of the ARPES data while leaving key aspects of the electronic structure and properties intact. The spectra show the clear opening of the charge density wave gap in the pure <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:mn>2</f:mn><f:mi>H</f:mi></f:mrow></f:math> phase and its suppression when <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mrow><g:mn>1</g:mn><g:mi>T</g:mi></g:mrow></g:math> layers are introduced to the system. Moreover, in the mixed-layer <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"><h:mrow><h:mn>4</h:mn><h:mi>H</h:mi><h:mi>b</h:mi></h:mrow></h:math> system, we observe a strongly momentum-anisotropic increase in electron-phonon coupling near the Fermi level relative to the <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"><i:mrow><i:mn>2</i:mn><i:mi>H</i:mi></i:mrow></i:math> phase. Both phenomena help to account for the increased <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"><j:msub><j:mi>T</j:mi><j:mi>c</j:mi></j:msub></j:math> in mixed <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"><k:mrow><k:mn>2</k:mn><k:mi>H</k:mi><k:mo>/</k:mo><k:mn>1</k:mn><k:mi>T</k:mi></k:mrow></k:math> layer structures. Published by the American Physical Society 2024