气候变化领域集成服务门户(CCPortal): Structural fluctuations cause spin-split states in tetragonal (CH 3 NH 3 )PbI 3 as evidenced by the circular photogalvanic effect

CCPortal

DOI	10.1073/pnas.1805422115
	Structural fluctuations cause spin-split states in tetragonal (CH 3 NH 3 )PbI 3 as evidenced by the circular photogalvanic effect
	Niesner D.; Hauck M.; Shrestha S.; Levchuk I.; Matt G.J.; Osvet A.; Batentschuk M.; Brabec C.; Weber H.B.; Fauster T.
发表日期	2018
ISSN	0027-8424
起始页码	9509
结束页码	9514
卷号	115 期号:38
英文摘要	Lead halide perovskites are used in thin-film solar cells, which owe their high efficiency to the long lifetimes of photocarriers. Various calculations find that a dynamical Rashba effect could significantly contribute to these long lifetimes. This effect is predicted to cause a spin splitting of the electronic bands of inversion-symmetric crystalline materials at finite temperatures, resulting in a slightly indirect band gap. Direct experimental evidence of the existence or the strength of the spin splitting is lacking. Here, we resonantly excite photocurrents in single crystalline (CH 3 NH 3 )PbI 3 with circularly polarized light to clarify the existence of spin splittings in the band structure. We observe a circular photogalvanic effect, i.e., the photocurrent depends on the light helicity, in both orthorhombic and tetragonal (CH 3 NH 3 )PbI 3 . At room temperature, the effect peaks for excitation photon energies ∆E = 110 meV below the direct optical band gap. Temperature-dependent measurements reveal a sign change of the effect at the orthorhombic–tetragonal phase transition, indicating different microscopic origins in the two phases. Within the tetragonal phase, both ∆E and the amplitude of the circular photogalvanic effect increase with temperature. Our findings support a dynamical Rashba effect in this phase, i.e., a spin splitting caused by thermally induced structural fluctuations which break inversion symmetry. © 2018 National Academy of Sciences. All rights reserved.
英文关键词	Circular photogalvanic effect; Dynamical rashba; Lead halide perovskite; Organic–inorganic perovskite; Rashba effect
语种	英语
scopus关键词	article; crystal structure; excitation; phase transition; photon; room temperature; temperature sensitivity
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160463
作者单位	Niesner, D., Lehrstuhl für Festkörperphysik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany; Hauck, M., Lehrstuhl für Angewandte Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany; Shrestha, S., Institute of Materials for Electronics and Energy Technology, Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany; Levchuk, I., Institute of Materials for Electronics and Energy Technology, Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany; Matt, G.J., Institute of Materials for Electronics and Energy Technology, Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany; Osvet, A., Institute of Materials for Electronics and Energy Technology, Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, E...
推荐引用方式 GB/T 7714	Niesner D.,Hauck M.,Shrestha S.,et al. Structural fluctuations cause spin-split states in tetragonal (CH 3 NH 3 )PbI 3 as evidenced by the circular photogalvanic effect[J],2018,115(38).
APA	Niesner D..,Hauck M..,Shrestha S..,Levchuk I..,Matt G.J..,...&Fauster T..(2018).Structural fluctuations cause spin-split states in tetragonal (CH 3 NH 3 )PbI 3 as evidenced by the circular photogalvanic effect.Proceedings of the National Academy of Sciences of the United States of America,115(38).
MLA	Niesner D.,et al."Structural fluctuations cause spin-split states in tetragonal (CH 3 NH 3 )PbI 3 as evidenced by the circular photogalvanic effect".Proceedings of the National Academy of Sciences of the United States of America 115.38(2018).