In:
Journal of Materials Chemistry C, Royal Society of Chemistry (RSC), Vol. 10, No. 33 ( 2022), p. 12032-12042
Abstract:
Thermal effects on the structure, bulk modulus ( B 0 ), and electronic band gap ( E g ) of the needle-like (NL) (NH 4 CdCl 3 structure type) and distorted perovskite (DP) (GdFeO 3 structure type) phases of SrZrS 3 were investigated over the temperature range 300–1200 K by means of ab initio molecular dynamics in an NPT ensemble, accelerated by adaptive machine learning. An anisotropic thermal expansion of a distinctly different quality was observed for the two phases. While all lattice vectors of the NL phase expand monotonously with T , the thermal behavior of the DP phase is more complex, with two vectors ( b and c ) monotonously expanding and one ( a ) contracting after an initial expansion. We show that the thermally-induced structural changes in the DP phase are a consequence of proximity of the cubic phase (C), into which it transforms quasi-continuously upon heating. A linear decrease of B 0 with T (from 45.9 GPa to 33.6 GPa for NL and from 66.8 GPa to 48.5 GPa for DP) is predicted. Since the temperature dependent E g values are determined as the NPT ensemble averages, both the lattice expansion and the electron–phonon coupling effects are naturally taken into account in our simulations. We found that the E g for NL is nearly constant, while that for DP decreases by as much as ∼0.5 eV within the studied temperature range. The latter is shown to be almost exclusively due to a very large atomic displacement contribution resulting from the proximity of the parent C phase, with the E g ∼ 0.8 eV lower than that of the DP phase.
Type of Medium:
Online Resource
ISSN:
2050-7526
,
2050-7534
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2022
detail.hit.zdb_id:
2702245-6
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