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Title: Inversion symmetry and bulk Rashba effect in methylammonium lead iodide perovskite single crystals

Methylammonium lead iodide perovskite (MAPbI 3) exhibits long charge carrier lifetimes that are linked to its high efficiency in solar cells. Yet, the mechanisms governing these unusual carrier dynamics are not completely understood. A leading hypothesis-disproved in this work-is that a large, static bulk Rashba effect slows down carrier recombination. Here, using second harmonic generation rotational anisotropy measurements on MAPbI 3 crystals, we demonstrate that the bulk structure of tetragonal MAPbI 3 is centrosymmetric with I4/ mcm space group. Our calculations show that a significant Rashba splitting in the bandstructure requires a non-centrosymmetric lead iodide framework, and that incorrect structural relaxations are responsible for the previously predicted large Rashba effect. The small Rashba splitting allows us to compute effective masses in excellent agreement with experiment. Here, our findings rule out the presence of a large static Rashba effect in bulk MAPbI 3, and our measurements find no evidence of dynamic Rashba effects.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4] ;  [3] ;  [2] ;  [2]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States); Trinity College Dublin, Dublin (Ireland)
  2. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  3. King Abdullah Univ. of Science and Technology (KAUST), Thuwal (Saudi Arabia)
  4. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 9; Journal Issue: 1; Related Information: © 2018 The Author(s).; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1460353