The stability, electronic and topological properties of Bi-doped <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>PbPdO</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> : a

Spin-gapless semiconductors (SGSs), as a new class of quantum materials, bridge conventional semiconductors and semi-metallic ferromagnets. Herein, the stability and topological properties of PbPdO₂with Bi substituting for Pb are systematically analyzed through first-principles calculations. The results show that Bi substitution for Pb is thermodynamically stable under Pb-poor conditions. Significantly, under the effect of spin-orbit coupling, the doped system demonstrates topological properties via topological order analysis, confirming its status as a topological material. Our results not only clarify the optimal growth conditions and topological nature ofPb0.5Bi0.5PdO2, but also reveal the inherent link between SGSs and non-trivial topological states, thereby offering a theoretical foundation for the design of innovative spintronic devices featuring efficient spin transport and topological protection.