Double-Rashba materials for nanocrystals with bright ground-state excitons
arXiv:2310.19678 · doi:10.1021/acsnano.4c02905
Abstract
While nanoscale semiconductor crystallites provide versatile fluorescent materials for light-emitting devices, such nanocrystals suffer from the "dark exciton"$\unicode{x2014}$an optically inactive electronic state into which the nanocrystal relaxes before emitting. Recently, a theoretical mechanism was discovered that can potentially defeat the dark exciton. The Rashba effect can invert the order of the lowest-lying levels, creating a bright excitonic ground state. To identify materials that exhibit this behavior, here we perform an extensive high-throughput computational search of two large open-source materials databases. Based on a detailed understanding of the Rashba mechanism, we define proxy criteria and screen over 500,000 solids, generating 173 potential "bright-exciton" materials. We then refine this list with higher-level first-principles calculations to obtain 28 candidates. To confirm the potential of these compounds, we select five and develop detailed effective-mass models to determine the nature of their lowest-energy excitonic state. We find that four of the five solids (BiTeCl, BiTeI, GaTe, and KIO) can yield bright ground-state excitons. Our approach thus reveals promising materials for future experimental investigation of bright-exciton nanocrystals.
19 pages, 4 figures
References in corpus (9)
- AFLOW: An automatic framework for high-throughput materials discovery
- Bright triplet excitons in lead halide perovskites
- Coherent Single Photon Emission from Colloidal Lead Halide Perovskite Quantum Dots
- Predicting Band Gaps with Hybrid Density Functionals
- Origin of giant bulk Rashba splitting: Application to BiTeI
- The Rashba Scale: Emergence of Band Anti-Crossing as a Design Principle for Materials with Large Rashba coefficient
- Lone-Pair Stereochemistry Induces Ferroelectric Distortion and the Rashba Effect in Inorganic Halide Perovskites
- Size-dependent lattice symmetry breaking determines the exciton fine structure of perovskite nanocrystals
- Orbital mapping of energy bands and the truncated spin polarization in three-dimensional Rashba semiconductors