Impact of symmetry breaking and spin-orbit coupling on the band gap of halide perovskites

Journal Article · Tue Jul 30 00:00:00 EDT 2024 · Physical Review. B

DOI:https://doi.org/10.1103/physrevb.110.035160· OSTI ID:2473206

Sabino, Fernando P. ^[1]; Zhao, Xin Gang ^[2]; Dalpian, Gustavo M. ^[3]; Zunger, Alex ^[2]

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1. University of São Paulo (Brazil); University of Colorado, Boulder, CO (United States); Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder
2. University of Colorado, Boulder, CO (United States)
3. University of São Paulo (Brazil)

Halide perovskite (HP) materials have recently emerged as a class of semiconductors with immense promise for various optoelectronic applications, ranging from solar cells to light-emitting diodes. One of the unique attributes of HPs is their tunable band gaps with different factors governing their value. Furthermore, the first factor is related to relativistic corrections [“mass-Darwin,” connected to the ns² lone pairs, and spin-orbit coupling (SOC)] that induce an orbital shift or degeneracy splitting, resulting in a band-gap reduction. The second factor involves the structural configuration: in HPs the local symmetry of each Wyckoff position tends to be broken, inducing an opening of the band gap. Based on high-throughput density functional theory calculations, this paper systematically studies a possible self-cancelation on the band-gap correction for HPs when the polymorphous configuration—structural effects—and the SOC—electronic effects—are included. Our results indicate that the nature of interplay between SOC and symmetry breaking (SB) is that they are independent decoupling effects to describe the band-gap magnitude in halide perovskites. As a result of that, we observe a transitivity of the band-gap description; i.e., if we know the band gap of halide perovskites without SB and SOC, we can independently add the effects of band-gap reduction due to SOC and band-gap opening due to SB, regardless of the order in which these effects are considered.

• Research Organization: University of Colorado, Boulder, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Solar Thermal, Biomass Power, and Hydrogen Technologies (EE-13)
• Grant/Contract Number: EE0009615
• OSTI ID: 2473206
• Alternate ID(s): OSTI ID: 2474295
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 3 Vol. 110; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
Perovskites
bandgap
density functional calculations
electronic structure
spin-orbit coupling
symmetry breaking states