Report
New-record-Tc and three-gap 2D superconductors with electronic and phononic topology: KB2C2
| العنوان: | New-record-Tc and three-gap 2D superconductors with electronic and phononic topology: KB2C2 |
|---|---|
| المؤلفون: | Liu, Hao-Dong, Fu, Xin-Peng, Fu, Zhen-Guo, Lu, Hong-Yan, Zhang, Ping |
| سنة النشر: | 2024 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Superconductivity |
| الوصف: | Pursuing higher-temperature superconductors under ambient pressure continues to be a prominent topic in materials discovery. Isomorphic structures like MgB2 exhibit potential for conventional BCS-type superconductivity, but their transition temperatures (Tc) have remained below 100 K based on both experimental findings and theoretical predictions. In this study, two new two-dimensional (2D) superconductors with sandwich structures,KB2C2,featuring BC layers in AA and AB stacking configurations,are designed, whose Tc can exceed 112 K,setting a new record in 2D superconductors. The analyses suggest that electrons in {\sigma}-states covalent bonds and high-frequency E phonon modes dominated by the in-plane vibrations of B/C atoms are predominately responsible for electron-phonon coupling (EPC). An exciting robust three-gap superconducting nature stems from the strong and evident three-region distribution characteristic of electronic EPC parameters {\lambda}. When biaxial tensile strain (BTS) is applied, their Tc are boosted above 153 K. The increase in Tc originates from the softening of optical E phonon modes around the {\Gamma} point and acoustic modes around the Q point, rather than an increase of electrons at the Fermi level (EF ) as observed in other similar systems. Thus, phonon plays a more beneficial role in the EPC of BTS cases, highlighting its significance as a medium in BCS superconductors. Moreover, we find KB2C2 exhibits interesting topological properties, spin antivortex, and Ising-type spin splitting. This is the first report of the coexistence of nontrivial topology and superconductivity with such a high Tc. Therefore, KB2C2 may offer promising sandwich structures to explore higher-Tc 2D superconductors, alongside present potential avenues for investigating fundamental quantum physics. Comment: 8 pages, 3 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2408.12242 |
| رقم الانضمام: | edsarx.2408.12242 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |