Theoretical prediction of superconductivity in monolayer h-BN doped with alkaline-earth metals (Ca, Sr, Ba)

Abstract

We investigated the possibility of superconductivity in monolayer hexagonal boron nitride (h-BN) doped using group-1 (Li, Na, K) and group-2 (Be, Mg, Ca, Sr, Ba) atoms via ab initio calculations. Consequently, we reveal that Sr-and Ba-doped monolayer h-BN and Ca-doped monolayer h-BN with 3.5% tensile strain are energetically stable and become superconductors with superconducting transition temperature (Tc) values of 5.83, 1.53, and 10.7 K, respectively, which are considerably higher than those of Ca-, Sr-, and Ba-doped graphene. In addition, the momentum-resolved electron-phonon coupling (EPC) constant shows that the scattering among intrinsic π * electrons around the Γ point governs Tc. The scattering process is mediated by the low-energy vibration of the adsorbate. Moreover, compared with graphene, the stronger adsorbate-substrate interaction and lower symmetry in h-BN are critical for enhancing the EPC in doped h-BN.

Phonon-Mediated Superconductivity near the Lattice Instability in Hole-doped Hydrogenated Monolayer Hexagonal Boron Nitride

“…The gating approach is similar to the case for biaxialtensile-strained and doped graphene (4.0× 10 14 holes cm −2 ) which shows the superconductivity with T c ∼30 K [21]. By means of chemical doping of Ca, Ba, and Sr atoms, one may theoretically obtain the superconductivity in monolayer h-BN with T c ranging from ∼1 K to 10 K [22]. The bilayer h-BN with an intercalated Li atom has also been predicted to show the superconductivity with different T c (< 25 K) [23,24].…”

“…Within this range of hole density, both the electron DOS and λ get enhanced with the increase of n. This result shows the correlation between EPC, DOS, and robust superconductivity [41]. In our calculations for T c , we adopted µ * = 0.13 which was used in [16] (note also that values of µ * are ranged from 0.10 to 0.14 [20,22,23]). It is important to notice that doping with higher carrier densities would cause the lattice to become unstable at 1.6× 10 14 holes cm −2 (see Fig.…”

Prediction of superconductivity in Li, K, Ca, and Sr-intercalated blue phosphorene bilayer using first-principle calculations

“…It is worthwhile to mention that in a recent experimental work, it was found that T C = 3.8 ± 0.1 K the Kintercalated black phosphorene bilayer [42]. The critical temperature for P-Ca-P compound is almost comparable with the bulk intercalation compound CaC 6 [65,66], and hBN-Ca [67]. Finally, the last compound P-Sr-P gives a superconducting transition temperature that is higher compared with the one obtained for monolayer h-BN doped with T C = 5.83 K [67].…”

Efficiency of electron doping to monolayer hexagonal boron nitride by alkali metals

“…We confirmed that even subsequent annealing did not promote intercalation of Ca, but desorption from the surface at 870 K. Although Ca is predicted to cause a larger shift than Cs based on its divalent nature, 8 it did not show intercalation or ionization in our experiments. A possible reason for that is given by a theory, 16 where the tensile strain of hBN is necessary to make the adsorption of Ca stable.…”