2021/08/25 by Peiyu Zhang, Xue Li, Xin Yang +3
Chemistry · Materials Science · Physics and Astronomy · #Chemistry #Clathrate hydrate #Cluster expansion #Condensed matter physics #Crystallography #High pressure #Hydrate #Iron-based superconductors research #Materials science #Physics #Rare-earth and actinide compounds #Superconductivity #Superconductivity in MgB2 and Alloys #Thermodynamics #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.105.094503
6 figures
arxiv created 2021/08/25 · openalex publication_date 2022/03/08 · arxiv updated 2022/03/23 · openalex created_date 2022/04/03 · openalex updated_date 2026/07/22
Recently, a host/guest clathrate SrB3C3 with sp3-bonded boron-carbon framework was synthesized at around 50 GPa. On the basis of electron count, the structure is understood as guest Sr2+ cations intercalated in the (B3C3)3- framework. Previous calculations suggest that SrB3C3 is a hole conductor with an estimated superconducting critical temperature (Tc) of 42 K at ambient pressure. If atoms with similar radius, such as Rb, can substitute Sr2+ in the lattice, the electronic as well as superconductivity properties of this material will be modified significantly. Here, we perform extensive simulations on the stability and physical properties of Rb-Sr-B3C3 system using first-principles density functional calculation in combination with cluster expansion and CALYPSO structure prediction method. We predict a phonon-mediated superconductor Rb0.5Sr0.5B3C3 with a remarkably high Tc of 78 K at ambient pressure, which is a significant improvement from the estimated value (42 K) in SrB3C3. The current results suggest that substitution of alkali atom in synthesized clathrate SrB3C3 is a viable route toward high-Tc compounds.