Predicted superconductivity above 100 K in electride <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi mathvariant="normal">L</mml:mi> <mml:msub> <mml:mi mathvariant="normal">i</mml:mi> <mml:mn>4</mml:mn> </mml:msub> <mml:mi>Rh</mml:mi> </mml:mrow> </mml:math> under high pressure

Abstract

Although numerous high-pressure electride (HPE) superconductors have been reported, their superconducting transition temperatures ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:msub> <a:mi>T</a:mi> <a:mi mathvariant="normal">c</a:mi> </a:msub> </a:math> ) are low. No HPE superconductor with a <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:msub> <c:mi>T</c:mi> <c:mi mathvariant="normal">c</c:mi> </c:msub> </c:math> exceeding 100 K has been reported. Herein, we predicted a HPE superconductor, <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:mrow> <e:mi mathvariant="normal">L</e:mi> <e:msub> <e:mi mathvariant="normal">i</e:mi> <e:mn>4</e:mn> </e:msub> <e:mi>Rh</e:mi> </e:mrow> </e:math> , with a high <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"> <h:mrow> <h:msub> <h:mi>T</h:mi> <h:mi mathvariant="normal">c</h:mi> </h:msub> <h:mo>=</h:mo> <h:mn>108.2</h:mn> </h:mrow> </h:math> K at 300 GPa, making it the first HPE superconductor with a <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"> <j:msub> <j:mi>T</j:mi> <j:mi mathvariant="normal">c</j:mi> </j:msub> </j:math> exceeding 100 K. <l:math xmlns:l="http://www.w3.org/1998/Math/MathML"> <l:mrow> <l:mi mathvariant="normal">L</l:mi> <l:msub> <l:mi mathvariant="normal">i</l:mi> <l:mn>4</l:mn> </l:msub> <l:mi>Rh</l:mi> </l:mrow> </l:math> features strong hybridization between nonnuclear attractors (NNAs) and atoms near the Fermi level and a large, deformed cylindrical Fermi sheet. This Fermi sheet structure induces strong electron-phonon coupling (EPC) and allows a broad range of electrons and phonons with a wide range of <o:math xmlns:o="http://www.w3.org/1998/Math/MathML"> <o:mi>q</o:mi> </o:math> vectors to participate in EPC, resulting in high <p:math xmlns:p="http://www.w3.org/1998/Math/MathML"> <p:msub> <p:mi>T</p:mi> <p:mi mathvariant="normal">c</p:mi> </p:msub> </p:math> . Unlike other HPE superconductors, the <r:math xmlns:r="http://www.w3.org/1998/Math/MathML"> <r:msub> <r:mi>T</r:mi> <r:mi mathvariant="normal">c</r:mi> </r:msub> </r:math> of <t:math xmlns:t="http://www.w3.org/1998/Math/MathML"> <t:mrow> <t:mi mathvariant="normal">L</t:mi> <t:msub> <t:mi mathvariant="normal">i</t:mi> <t:mn>4</t:mn> </t:msub> <t:mi>Rh</t:mi> </t:mrow> </t:math> does not decrease with decreasing EPC but remains stable because the logarithmic average phonon frequency increases as the EPC strength decreases. This helps maintain <w:math xmlns:w="http://www.w3.org/1998/Math/MathML"> <w:msub> <w:mi>T</w:mi> <w:mi mathvariant="normal">c</w:mi> </w:msub> </w:math> with increasing pressure with little fluctuation. The results indicate that HPEs with strong hybridization between NNAs and atoms near the Fermi level and with large and closed Fermi surfaces are more likely to exhibit high <y:math xmlns:y="http://www.w3.org/1998/Math/MathML"> <y:msub> <y:mi>T</y:mi> <y:mi mathvariant="normal">c</y:mi> </y:msub> </y:math> , offering deep insights into HPE superconductivity and providing valuable guidance for future research into high- <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML"> <ab:msub> <ab:mi>T</ab:mi> <ab:mi mathvariant="normal">c</ab:mi> </ab:msub> </ab:math> electrides.

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