Physical properties and electronic structure of the two-gap superconductor V2Ga5

We present a thorough investigation of the physical properties and superconductivity of the binary intermetallic <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi mathvariant="normal">V</a:mi><a:mn>2</a:mn></a:msub><a:msub><a:mi>Ga</a:mi><a:mn>5</a:mn></a:msub></a:mrow></a:math>. Electrical resistivity and specific heat measurements show that <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:msub><c:mi mathvariant="normal">V</c:mi><c:mn>2</c:mn></c:msub><c:msub><c:mi>Ga</c:mi><c:mn>5</c:mn></c:msub></c:mrow></c:math> enters its superconducting state below <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mrow><e:msub><e:mi>T</e:mi><e:mrow><e:mi>s</e:mi><e:mi>c</e:mi></e:mrow></e:msub><e:mo>=</e:mo></e:mrow></e:math> 3.5 K, with a critical field of <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:msub><f:mi>H</f:mi><f:mrow><f:mrow><f:mi mathvariant="normal">c</f:mi><f:mn>2</f:mn></f:mrow><f:mo>,</f:mo><f:mo>⊥</f:mo><f:mi mathvariant="normal">c</f:mi></f:mrow></f:msub><f:mrow><f:mo>(</f:mo><f:msub><f:mi>H</f:mi><f:mrow><f:mrow><f:mi mathvariant="normal">c</f:mi><f:mn>2</f:mn></f:mrow><f:mo>,</f:mo><f:mo>|</f:mo><f:mo>|</f:mo><f:mi mathvariant="normal">c</f:mi></f:mrow></f:msub><f:mo>)</f:mo></f:mrow><f:mo>=</f:mo><f:mn>6.5</f:mn><f:mrow><f:mo>(</f:mo><f:mn>4.1</f:mn><f:mo>)</f:mo></f:mrow></f:mrow></f:math> kOe. With <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"><k:mrow><k:mi>H</k:mi><k:mo>⊥</k:mo><k:mi>c</k:mi></k:mrow></k:math>, the peak effect was observed in resistivity measurements, indicating the ultrahigh quality of the single crystal studied. The resistivity measurements under high pressure reveal that the <l:math xmlns:l="http://www.w3.org/1998/Math/MathML"><l:msub><l:mi>T</l:mi><l:mrow><l:mi>s</l:mi><l:mi>c</l:mi></l:mrow></l:msub></l:math> is suppressed linearly with pressure and reaches absolute zero around 20 GPa. Specific heat and muon spin relaxation measurements indicate that the two-gap <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mi>s</m:mi></m:math>-wave model best describes the superconductivity of <n:math xmlns:n="http://www.w3.org/1998/Math/MathML"><n:mrow><n:msub><n:mi mathvariant="normal">V</n:mi><n:mn>2</n:mn></n:msub><n:msub><n:mi>Ga</n:mi><n:mn>5</n:mn></n:msub></n:mrow></n:math>. The bands near the Fermi level around the <p:math xmlns:p="http://www.w3.org/1998/Math/MathML"><p:mi>Z</p:mi></p:math> and <q:math xmlns:q="http://www.w3.org/1998/Math/MathML"><q:mi mathvariant="normal">Γ</q:mi></q:math> points are observed and analyzed by the angle-resolved photoemission spectroscopy measurements and first-principles band structure calculations. We therefore conclude that <s:math xmlns:s="http://www.w3.org/1998/Math/MathML"><s:mrow><s:msub><s:mi mathvariant="normal">V</s:mi><s:mn>2</s:mn></s:msub><s:msub><s:mi>Ga</s:mi><s:mn>5</s:mn></s:msub></s:mrow></s:math> is a phonon-mediated two-gap <u:math xmlns:u="http://www.w3.org/1998/Math/MathML"><u:mi>s</u:mi></u:math>-wave superconductor. Published by the American Physical Society 2024