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Your search keyword '"Li, Guan"' showing total 6 results
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6 results on '"Li, Guan"'

4. Effect of atomic configuration on band gap behaviour in CH3NH3Sn Pb1−I3 perovskites

Author

Yanan Liang, Jianglong Wang, Shichuang Han, Xu Li, Xiaofang Xu, Jianxin Guo, and Li Guan

Subjects
Physics, Band gap, Stacking, General Physics and Astronomy, Halide, 01 natural sciences, 010305 fluids & plasmas, Tetragonal crystal system, Crystallography, Atomic configuration, Atomic orbital, Octahedron, 0103 physical sciences, 010306 general physics, Perovskite (structure)
Abstract

The atomic structure and electronic properties of Sn/Pb mixed organometal halide perovskites were investigated by using first-principles method. The structure-dependent band gap behaviour of tetragonal and pseudocubic MASnxPb1−xI3 ( 0 ⩽ x ⩽ 1 ) was emphasized. The configurations with two or more adjacent Sn octahedra in the same layer inducing less tilting of neighbouring octahedra have the lower formation energy. For tetragonal or pseudocubic MASn0.5Pb0.5I3, the configuration of Sn octahedra layer alternating with Pb octahedra layer leads to elongated octahedra along the stacking direction, which stimulates the remarkable band splitting due to anomalous hybridization of Pb or Sn orbitals and I orbitals. This arrangement mode of Sn octahedra produces the narrowest band gap of Sn/Pb binary perovskite, whereas the separated and dispersed Sn octahedra significantly broaden the band gap. The results are helpful to understand the abnormal band gap behaviour in Sn/Pb binary perovskite experiments.

Published
2020

6. Theoretical study of magnetic phase transition in La[formula omitted]M[formula omitted]MnO3 (M=Ca, Sr) membranes through strain and doping.

Author

Lin, Jia-Yi, Chen, Zhong-Jia, Li, Guan-Liang, Zeng, Jiarui, Cen, Yu-Jie, Xie, Wen-Qiang, Peng, Yin-Hui, Liao, Ji-Hai, Yang, Xiao-Bao, and Zhao, Yu-Jun

Subjects
*MAGNETIC transitions, *MAGNETIC structure, *CARRIER density, *CALCIUM ions, *MAGNETIC moments, *MAGNETIC properties
Abstract

The antiferromagnetic-semiconductor extreme tensile strain (8%) states of La 0.7 Ca 0.3 MnO 3 membranes was achieved by Hong et al. (2020) [23]. To understand such tunable magnetic and electronic properties in these La 2 3 M 1 3 MnO 3 (M=Ca, Sr) systems, we have investigated the magnetic and electronic behaviors of La 2 3 M 1 3 MnO 3 (M=Ca, Sr) under strain and charge doping using first-principles calculations. A ferromagnetic-semiconductor phase is predicted for La 2 3 Sr 1 3 MnO 3 beyond 4% biaxial tensile strain. Meanwhile, its energy gap and magnetic anisotropic energy increase as the strain increases. We also discover that the change of magnetic exchange energy in La 2 3 Ca 1 3 MnO 3 under charge doping is in analogy to the scenario directly changing the Ca concentrations. Based on the magnetic competition analysis, it is expected that the carrier concentration and strains dominate the magnetic ground state while the La/Ca distributions have little impact. The highly tunable magnetic-electronic properties offer opportunities for the future magnetic-electronic materials design and applications. • DFT SCAN calculations give excellent structure and magnetic moments of the studied systems. • A ferromagnetic semiconductor is predicted for La 2/3 Sr 1/3 MnO 3 under biaxial tensile strain. • Carrier concentration combined with strains dominate the magnetic coupling. • Magnetic anisotropic energy is enhanced by 30 μeV by strains for La 2/3 Sr 1/3 MnO 3. [ABSTRACT FROM AUTHOR]

Published
2022
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