Crystal Structure of BaFe2Se3 as a Function of Temperature and Pressure: Phase Transition Phenomena and High-Order Expansion of Landau Potential

Abstract

BaFe2Se3 (Pnma, CsAg2I3-type structure), recently assumed to show superconductivity at ~ 11 K, exhibits a pressure-dependent structural transition to the CsCu2Cl3-type structure (Cmcm space group) around 60 kbar, as evidenced from pressure-dependent synchrotron powder diffraction data. Temperature-dependent synchrotron powder diffraction data indicate an evolution of the room-temperature BaFe2Se3 structure towards a high symmetry CsCu2Cl3 form upon heating. Around 425 K BaFe2Se3 undergoes a reversible, first order isostructural transition, that is supported by the differential scanning calorimetry data. The temperature-dependent structural changes occur in two stages, as determined by the alignment of the FeSe4 tetrahedra and corresponding adjustments of the positions of Ba atoms. On further heating, a second order phase transformation into the Cmcm structure is observed at 660 K. A rather unusual combination of isostructural and second-order phase transformations is parameterized within phenomenological theory assuming high-order expansion of Landau potential. A generic phase diagram mapping observed structures is proposed on the basis of the parameterization.

22 pages, 15 figures

References in corpus (4)

• Iron Displacements and Magnetoelastic Coupling in the Spin-Ladder Compound BaFe2Se3
• Anisotropy in BaFe2Se3 single crystals with double chains of FeSe tetrahedra
• Iron isotope effect on the superconducting transition temperature and the crystal structure of FeSe_1-x
• Spin Glass and Semiconducting Behavior in 1D BaFe2-δSe3 Crystals

Cited by in corpus (14)

• BaFe${}_2$Se${}_3$: a high $T_{\mathrm{C}}$ magnetic multiferroic with large ferrielectric polarization
• Sequential structural and antiferromagnetic transitions in BaFe${}_2$Se${}_3$ under pressure
• The magnetic precursor of the pressure-induced superconductivity in Fe-ladder compound
• Fingerprints of an Exotic Orbital-Selective Mott Phase in the Block Magnetic State of BaFe${}_2$Se${}_3$ Ladders
• Iron telluride ladder compounds: Predicting the structural and magnetic properties of BaFe${}_2$Te${}_3$
• High-pressure polymorphism of BaFe2Se3
• Polar State induced by Block-type Lattice Distortions in BaFe2Se3 with Quasi-One-Dimensional Ladder Structure
• Strong electronic correlations and Fermi surface reconstruction in the quasi-one dimensional iron superconductor BaFe2S3
• Direct Visualization of Irreducible Ferrielectricity in Crystals
• Pressure-Induced Metallization in Iron-Based Ladder Compounds Ba${}_{1-x}$Cs${}_x$Fe${}_2$Se${}_3$
• Magnetic-order-driven metal-insulator transitions in the quasi-one-dimensional spin-ladder compounds BaFe${}_2$S${}_3$ and BaFe${}_2$Se${}_3$
• Magnetism of BaFe2Se3 studied by Mössbauer spectroscopy
• Pressure-induced superconductivity in iron-based spin-ladder compound BaFe2+δ(S1-Sex)3
• The role of the nominal iron content in the structural, compositional and physical properties of BaFe${}_{2+\delta }$S${}_3$