title: GeP3: A Small Indirect Band Gap 2D Crystal with High Carrier Mobility and Strong Interlayer Quantum Confinement.
abstract: We propose a two-dimensional crystal that 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. GeP3has a stable three-dimensional layered bulk counterpart, which is metallic and known from experiment since 1970. GeP3monolayer has a calculated cleavage energy of 1.14 J m-2, 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.
authors.affiliation: Wilhelm-Ostwald-Institute for Physical und Theoretical Chemistry, Leipzig University , Linnéstrasse 2, 04103 Leipzig, Germany.|Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Yu
authors.initials: Y
authors.lastname: Jing
authors.affiliation: Wilhelm-Ostwald-Institute for Physical und Theoretical Chemistry, Leipzig University , Linnéstrasse 2, 04103 Leipzig, Germany.
authors.forename: Yandong
authors.initials: Y
authors.lastname: Ma
authors.affiliation: College of Chemistry and Materials Science, Jiangsu Key Laboratory of Biofunctional Materials, Nanjing Normal University , Nanjing, Jiangsu 210023, China.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Li
authors.affiliation: Wilhelm-Ostwald-Institute for Physical und Theoretical Chemistry, Leipzig University , Linnéstrasse 2, 04103 Leipzig, Germany.|Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Thomas
authors.identifier: 0000-0003-2379-6251
authors.initials: T
authors.lastname: Heine
keywords: 2D crystals; black phosphorus; blue phosphorus; density functional theory; electronic properties; germanium phosphide; low band gap; phosphorene