Density functional theory investigation of the LiIn_1-xGa_xSe₂ solid solution

Journal Article · 07 June 2016 · Physica Status Solidi B. Basic Solid State Physics

DOI: https://doi.org/10.1002/pssb.201600273 · OSTI ID:1346704

Wiggins, Brenden ^[1]; Batista, Enrique ^[2]; Burger, Arnold ^[3]; Stassun, Keivan ^[3]; Stowe, Ashley ^[4]

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1. Y-12 National Security Complex, Oak Ridge, TN (United States); Vanderbilt Univ., Nashville, TN (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. Vanderbilt Univ., Nashville, TN (United States); Fisk Univ., Nashville, TN (United States)
4. Y-12 National Security Complex, Oak Ridge, TN (United States); Vanderbilt Univ., Nashville, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)

Here, the electronic structure and optical properties of the LiIn_1-xGa_xSe₂ (x=0, 0.25, 0.5, 0.75, 1) solid solution were studied by density functional theory (DFT) with pure functionals. The exchange-correlation is treated within the local density approximation (LDA) and generalized-gradient approximation (GGA). The electronic structures for each respective compound are discussed in detail. Calculations reveal that gallium incorporation can be used to tune the optical-electrical properties of the solid solution and correlates with the lattice parameter. The band gap trend of the LiIn_1-xGa_xSe₂ system follows a nonlinear behavior between the LiInSe₂ and LiGaSe₂ ternary boundaries. The bowing parameter is estimated to be on the order of 0.1- 0.3 eV at the point. Low-temperature optical absorption revealed a 30% change in the temperature dependence of the band gap for the intermediate compound LiIn_0.6Ga_0.4Se₂ compared to ternary boundaries and suggests the heat capacity to be another control element through strain.

• Research Organization: Oak Ridge Y-12 Plant (Y-12), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: NA0001942
• OSTI ID: 1346704
• Report Number(s): MS/STO-160314-3
• Journal Information: Physica Status Solidi B. Basic Solid State Physics, Vol. 253, Issue 8; ISSN 0370-1972
• Publisher: Wiley-BlackwellCopyright Statement
• Country of Publication: United States
• Language: English