报告题目：Optimal coloring and strain-enhanced superconductivity in Li_nB_n+1C_n-1 

报 告 人：顾雨豪，北京科技大学数理学院

报告时间：2026年4月20日（星期一）上午10:00

报告地点：物理楼313会议室

报告摘要：Boron-rich lithium borocarbides ( Li_nB_n+1C_n-1 ) are promising candidates for phonon-mediated high-temperature superconductors due to their metallic σ-bonding electrons. In the first work, we identify the energetically stable configurations (colorings) of Li₂B₃C and Li₃B₄C₂ using the cluster expansion method, which are characterized by a distinctive pattern of alternating B-B and B-C zigzag chains. Surprisingly, the optimal configuration of Li₂B₃C exhibits an extremely low superconducting transition temperature (T_C < 0.03 K) due to the suppression of deformation potentials near the Fermi level. However, the σ-bonding electrons at the Fermi level are highly sensitive to external strain. Applying a -5% compressive uniaxial strain along the b-axis significantly enhances the electron-phonon coupling and deformation potential, boosting T_C to ~37 K. Furthermore, in the second work, we introduce a descriptor Δε, defined as the energy offset between the maximum of the B-B bridge σ-bonding band and the Fermi level, to systematically screen biaxially strained structures. We demonstrate that a combination of +5% tensile strain along the a-axis and -5% compressive strain along the b-axis optimally lifts the top of the B-B bridge σ-bonding band, resulting in a maximum T_C of 44.7 K. Our results indicate that achieving strong electron-phonon coupling requires not only the presence of σ-bonding character but also a significant deformation potential. This deepened understanding not only presents a strategy for achieving high critical temperatures in Li_nB_n+1C_n-1 compounds, but also provides valuable insights into the complex interplay between electronic structure and superconducting interaction.

个人简介：顾雨豪，北京科技大学数理学院教师。2014年本科毕业于南京大学，2019年博士毕业于北京大学，后在PG电子平台物理研究所从事博士后研究，2024年加入北京科技大学。主要研究领域为固体材料电子结构计算及其新奇物性，曾主持国家自然科学基金青年项目及中国博士后科学基金特别资助项目。近年来在 Communications Physics、Physical Review B、Chinese Physics Letters 等期刊发表多篇研究论文。

供稿审核：刘广强

编辑审核：王文志

终审：满忠晓