We demonstrate an approach for calculating temperature-dependent quantum and anharmonic effects with beyond density-functional theory accuracy. By combining machine-learned potentials and the stochastic self-consistent harmonic approximation, we investigate the cubic to tetragonal transition in strontium titanate and show that the paraelectric phase is stabilized by anharmonic quantum fluctuations. We find that a quantitative understanding of the quantum paraelectric behavior requires a higher-level treatment of electronic correlation effects via the random phase approximation. This approach enables detailed studies of emergent properties in strongly anharmonic materials beyond density-functional theory.

Quantum paraelectricity and structural phase transitions in strontium titanate beyond density functional theory / Verdi, Carla; Ranalli, Luigi; Franchini, Cesare; Kresse, Georg. - In: PHYSICAL REVIEW MATERIALS. - ISSN 2475-9953. - ELETTRONICO. - 7:3(2023), pp. L030801.1-L030801.6. [10.1103/PhysRevMaterials.7.L030801]

Quantum paraelectricity and structural phase transitions in strontium titanate beyond density functional theory

Franchini, Cesare
Penultimo
Supervision
;
2023

Abstract

We demonstrate an approach for calculating temperature-dependent quantum and anharmonic effects with beyond density-functional theory accuracy. By combining machine-learned potentials and the stochastic self-consistent harmonic approximation, we investigate the cubic to tetragonal transition in strontium titanate and show that the paraelectric phase is stabilized by anharmonic quantum fluctuations. We find that a quantitative understanding of the quantum paraelectric behavior requires a higher-level treatment of electronic correlation effects via the random phase approximation. This approach enables detailed studies of emergent properties in strongly anharmonic materials beyond density-functional theory.
2023
Quantum paraelectricity and structural phase transitions in strontium titanate beyond density functional theory / Verdi, Carla; Ranalli, Luigi; Franchini, Cesare; Kresse, Georg. - In: PHYSICAL REVIEW MATERIALS. - ISSN 2475-9953. - ELETTRONICO. - 7:3(2023), pp. L030801.1-L030801.6. [10.1103/PhysRevMaterials.7.L030801]
Verdi, Carla; Ranalli, Luigi; Franchini, Cesare; Kresse, Georg
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/957797
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