First-principles prediction of superconductivity in MgB3C3

Exploration of AB3Si3 (A = Na/K/Rb/Cs) compounds under moderate pressure

“…16 Subsequently, superconductivity was confirmed through experiments 17 and density functional theory (DFT) calculations. 16,18 This discovery inspired numerous studies on related materials, 19–23 extending even to quaternary borocarbides by substituting different guest atoms. 16,24,25 Silicon-based materials, as the closest neighbor of carbon in elemental group IVA, are also extensively studied.…”

Prospect of high-temperature superconductivity in layered metal borocarbides

“…, at high pressures) and/or morphology ( e.g. , in 2D or clathrate forms): Li 4 B 5 C 2 , 22 Li 3 B 4 C 2 , 23 2D LiB 2 C 2 , 24 Li 2 x BC 3 , 25 M x BC 2 , 26 MgB 3 C 3 , 27 2D Mg 2 B 4 C 2 , 28 X–Y–B 2 , 29 Li–B–C, 30 and X–Y–B 6 C 6 . 31 While the feasibility of obtaining our identified quaternary phases depends on a number of kinetic and thermodynamic factors that require further study, the findings dramatically expand the search space for high- T c ambient-pressure superconductors.…”

Why Yttrium Hexaboride Exhibits a Much Higher Superconducting Tc than Near-Identical Lanthanum Hexaboride

“…[2,[9][10][11][12][13][14][15] Lanthanum hexaboride, though primarily exploited in hot cathodes for its high electron emissivity, is also known to be a low-temperature, Bardeen-Cooper-Schrieffer (BCS, i.e phonon-mediated) superconductor at temperatures below 0.45 K. [16] Isostructural yttrium hexaboride, possessing a near-identical phonon spectrum, a similar lattice constant (4.155 Å for LaB6, 4.098 Å for YB6), and yttrium being one row directly above lanthanum in the periodic table, is a significantly better BCS superconductor at a critical temperature (Tc) of up to 8.4 K. [17][18][19] This notably makes it the only reported superconducting hexaboride with a Tc reachable with 4 He cryogenics. [20,21] It also possesses the second highest superconducting Tc of any metal boride [22] , the highest being that of the unusual [23] and thoroughly studied MgB2 [24][25][26][27][28] , the highest-Tc "conventional" (i.e. phonon-mediated) superconductor.…”