Browsing by Author "Wang, Yifeng"

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Strain robust spin gapless semiconductors/half-metals in transition metal embedded MoSe2monolayer
(2020-08-26) Yang, Qiang; Kou, Liangzhi; Hu, Xiaohui; Wang, Yifeng; Lu, Chunhua; Krasheninnikov, Arkady V.; Sun, Litao
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The realization of spin gapless semiconductor (SGS) and half-metal (HM) behavior in two-dimensional (2D) transition metal (TM) dichalcogenides is highly desirable for their applications in spintronic devices. Here, using density functional theory calculations, we demonstrate that Fe, Co, Ni substitutional impurities can not only induce magnetism in MoSe2 monolayer, but also convert the semiconducting MoSe2 to SGS/HM system. We also study the effects of mechanical strain on the electronic and magnetic properties of the doped monolayer. We show that for all TM impurities we considered, the system exhibits the robust SGS/HM behavior regardless of biaxial strain values. Moreover, it is found that the magnetic properties of TM-MoSe2 can effectively be tuned under biaxial strain by controlling the spin polarization of the 3d orbitals of Fe, Co, Ni atoms. Our findings offer a new route to designing the SGS/HM properties and modulating magnetic characteristics of the TM-MoSe2 system and may also facilitate the implementation of SGS/HM behavior and realization of spintronic devices based on other 2D materials.
Tunable electronic properties and enhanced ferromagnetism in Cr2Ge2Te6monolayer by strain engineering
(2021-11-26) Liu, Lifei; Hu, Xiaohui; Wang, Yifeng; Krasheninnikov, Arkady V.; Chen, Zhongfang; Sun, Litao
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Recently, as a new representative of Heisenberg's two-dimensional (2D) ferromagnetic materials, 2D Cr2Ge2Te6 (CGT), has attracted much attention due to its intrinsic ferromagnetism. Unfortunately, the Curie temperature (T C ) of CGT monolayer is only 22 K, which greatly hampers the development of the applications based on the CGT materials. Herein, by means of density functional theory computations, we explored the electronic and magnetic properties of CGT monolayer under the applied strain. It is demonstrated that the band gap of CGT monolayer can be remarkably modulated by applying the tensile strain, which first increases and then decreases with the increase of tensile strain. In addition, the strain can increase the Curie temperature and magnetic moment, and thus largely enhance the ferromagnetism of CGT monolayer. Notably, the obvious enhancement of T C by 191% can be achieved at 10% strain. These results demonstrate that strain engineering can not only tune the electronic properties, but also provide a promising avenue to improve the ferromagnetism of CGT monolayer. The remarkable electronic and magnetic response to biaxial strain can also facilitate the development of CGT-based spin devices.