arXiv subjects

Yafei Li

Publications and source records attributed to Yafei Li.

21 records · Page 2Linked to original sources

arXiv2017

GeP3: A small indirect band gap 2D crystal with high carrier mobility and strong interlayer quantum confinement

We propose a two-dimensional crystal which possesses low indirect band gaps of 0.55 eV (monolayer) and 0.43 eV (bilayer) and high carrier mobilities similar to those of phosphorene: GeP3. GeP3 has a stable three-dimensional layered bulk counterpart which is metallic and is known from experiment since 1970. It has a small cleavage energy, which suggests exfoliation of bulk material as viable means for the preparation of mono- and few-layer materials. The material shows strong interlayer quantum confinement effects, resulting in a band gap reduction from mono- to bilayer, and then to a semiconductor-metal transition between bi- and triple layer. Under biaxial strain, the indirect band gap can be turned into a direct one. Pronounced light absorption in the spectral range from ~600 to 1400 nm is predicted for monolayer and bilayer and promises applications in photovoltaics.

cond-mat.mtrl-sci↗

arXiv2016

Dirac Nodal Lines and Tilted Semi-Dirac Cones Coexisting in a Striped Boron Sheet

The enchanting Dirac fermions in graphene stimulated us to seek for other two-dimensional (2D) Dirac materials, and boron monolayers may be a good candidate. So far, a number of monolayer boron sheets have been theoretically predicted, and three have been experimentally prepared. However, none of them possesses Dirac electrons. Herein, by means of density functional theory (DFT) computations, we identified a new boron monolayer, namely hr-sB, with two types of Dirac fermions coexisting in the sheet: one type is related to Dirac nodal lines traversing Brillouin zone (BZ) with velocities approaching 106 m/s, the other is related to tilted semi-Dirac cones with strong anisotropy. This newly predicted boron monolayer consists of hexagon and rhombus stripes. With an exceptional stability comparable to the experimentally achieved boron sheets, it is rather optimistic to grow hr-sB on some suitable substrates such as the Ag (111) surface. The unique electronic properties induced by special bond characteristics also imply that this boron monolayer may be a good superconductor.

cond-mat.mes-hall↗

arXiv2008

Electronic Structures of SiC Nanoribbons

Electronic structures of SiC nanoribbons have been studied by spin-polarized density functional calculations. The armchair nanoribbons are nonmagnetic semiconductor, while the zigzag nanoribbons are magnetic metal. The spin polarization in zigzag SiC nanoribbons is originated from the unpaired electrons localized on the ribbon edges. Interestingly, the zigzag nanoribbons narrower than $\sim$4 nm present half-metallic behavior. Without the aid of external field or chemical modification, the metal-free half-metallicity predicted for narrow SiC zigzag nanoribbons opens a facile way for nanomaterial spintronics applications.

cond-mat.mtrl-sci↗