Computational Design of One-Dimensional Ferromagnetic Semiconductors in Transition Metal Embedded Stannaspherene Nanowires

Developing low dimensional semiconductors with moderate band gaps,intrinsic ferromagnetism and large magnetic anisotropy energies (MAEs) is very desirable for high-speed nano-spintronic devices,which,however,still remains a big challenge.Here,via first principles calculations,a potential route to realize such materials is proposed based on a new class of one-dimensional transition metal (TM) embedded stannaspherene (Sn122-) nanowires [TM2(Sn12)]∞ (TM =Ti-Ni).Three semiconductors with robust ferromagnetism are achieved with TM =V,Cr and Fe,which all exhibit direct or quasi-direct band gaps around 1.0 eV,rendering their great potentials for visible light optoelectronic applications.Interestingly,[Cr2(Sn12)]∞ and [Fe2(Sn12)]∞ are both identified as bipolar magnetic semiconductors (BMS) with valence and conduction band edges spin polarized in the opposite directions,which are promising for realizing switch of carriers' spin orientation by electrical gating,while [V2(Sn12)]∞ exhibits a half semiconductor (HSC) property with valence and conduction band edges spin polarized in the same direction and can be used for spin-polarized carriers generation.Moreover,sizable MAEs are discovered in these nanowires,which are at least two orders of magnitude larger than those of Fe,Co and Ni bulks and also significantly larger than current ferromagnetic semiconductors.