Tunable magnetism by nonmagnetic-doping in 2D flexible alkaline-earth metal halofluoride XYF (X = Ca/Sr/Ba, Y = Cl/Br/I) with ultra-wide bandgap

Nowadays, Alkaline earth metal halofluoride, as part of layered materials, have drawn considerable interest for applications in optoelectronic devices and sensors, benefiting from wide bandgap properties. In this work, the monolayer alkaline earth metal halofluoride XYF (X = Ca/Sr/Ba, Y = Cl/Br/I) were investigated based on first-principles calculations. These monolayers can be exfoliated with energies comparable to conventional two-dimensional (2D) materials, suggesting their potential for practical applications. Additionally, XYF monolayers all exhibit excellent structural stability, with a maximum elastic modulus ranging from 37.144 to 76.829 N/m, indicating significant flexibility. More strikingly, these materials are characterized as ultra-wide bandgap (UWBG) semiconductors, with direct bandgaps spanning from 5.06 to 7.56 eV using HSE06 functional. Furthermore, exploration was conducted into introducing magnetism by doping of S and P atoms, thereby providing magnetic moments in non-magnetic systems. Our research broadens the spectrum of 2D wide-bandgap materials, and holds promise for their applications in optoelectronics, flexible electronics and spintronics.