Non-centrosymmetric, transverse structural modulation in SrAl4, and elucidation of its origin in the BaAl4 family of compounds

Abstract

At ambient conditions SrAl4 adopts the BaAl4 structure type with space group I4/mmm. It undergoes a charge-density-wave (CDW) transition at TCDW = 243 K, followed by a structural transition at TS = 87 K. Temperature-dependent single-crystal X-ray diffraction (SXRD) leads to the observation of incommensurate superlattice reflections at q = σc* with σ= 0.1116 at 200 K. The CDW has orthorhombic symmetry with the acentric superspace group F222(00sigma)00s, where F222 is a subgroup of Fmmm as well as of I4/mmm. Atomic displacements mainly represent a transverse wave, with displacements that are 90 deg out of phase between the two diagonal directions of the I-centered unit cell, resulting in a helical wave. Small longitudinal displacements are provided by the second harmonic modulation. The orthorhombic phase realized in SrAl4 is similar to that found in EuAl4. Electronic structure calculations and phonon calculations by density functional theory (DFT) have failed to reveal the mechanism of CDW formation. However, DFT reveals that Al atoms dominate the density of states near the Fermi level, thus, corroborating the SXRD measurements. SrAl4 remains incommensurately modulated at the structural transition, where the symmetry lowers from orthorhombic to b-unique monoclinic. We have identified a simple criterion, that correlates the presence of a phase transition with the interatomic distances. Only those compounds XAl4-xGax(X = Ba, Eu, Sr, Ca; 0 < x <4) undergo phase transitions, for which the ratio c/a falls within the narrow range 2.51 < c/a < 2.54.

References in corpus (31)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Wannier90: A Tool for Obtaining Maximally-Localised Wannier Functions
• Maximally localized Wannier functions: Theory and applications
• WannierTools: An open-source software package for novel topological materials
• Fermi surface nesting and the origin of Charge Density Waves in metals
• Electronic crystals: an experimental overview
• Irvsp: to obtain irreducible representations of electronic states in the VASP
• Discovery of charge density wave in a correlated kagome lattice antiferromagnet
• Intertwined magnetism and charge density wave order in kagome FeGe
• Tunable nodal kagome superconductivity in charge ordered RbV3Sb5
• Unique Helical Magnetic Order and Field-Induced Phase in Trillium Lattice Antiferromagnet EuPtSi
• Anomalous Hall resistivity and possible topological Hall effect in the EuAl${}_4$ antiferromagnet
• Coexistence of Multiple Stacking Charge Density Waves in Kagome Superconductor ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$
• Charge-Density-Wave Order and Multiple Magnetic Transitions in Divalent Europium Compound EuAl${}_4$
• Structural evolution of the kagome superconductors $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, and Cs) through charge density wave order
• Spin order and fluctuations in the EuAl${}_4$ and EuGa${}_4$ topological antiferromagnets: A $\mu$SR study
• Incommensurate magnetic orders and topological Hall effect in the square-net centrosymmetric EuGa${}_2$Al${}_2$ system
• Rhombic skyrmion lattice coupled with orthorhombic structural distortion in EuAl${}_4$
• Thermodynamic insights into the intricate magnetic phase diagram of EuAl${}_4$
• Charge density wave behavior and order-disorder in the antiferromagnetic metallic series Eu(Ga_1-xAl_x)_4
• Orthorhombic charge density wave on the tetragonal lattice of EuAl4
• Magnetic interactions and possible structural distortion in kagome FeGe from first-principles study and symmetry analysis
• Charge fluctuations above $T_{\mathrm{CDW}}$ revealed by glasslike thermal transport in kagome metals $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, Cs)
• Superconductivity in the Ru-Doped CuIr2Te4 Telluride Chalcogenide
• The structure of kagome superconductors CsV${}_3$Sb${}_5$ in the charge density wave states
• Electronic Correlations and Evolution of the Charge-Density Wave in the Kagome Metals $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, Cs)
• Coupling between colossal charge density wave ordering and magnetism in Ho2Ir3Si5
• Origin of Charge Density Wave in Topological Semimetals SrAl4 and EuAl4
• Charge-density wave transition in magnetic topological semimetal EuAl${}_4$
• Observation of a flat and extended surface state in a topological semimetal

Cited by in corpus (6)

• Experimental progress in Eu(Al,Ga)${}_4$ topological antiferromagnets
• Electron-phonon coupling in EuAl4 under hydrostatic pressure
• I-centered vs F-centered orthorhombic symmetry and negative thermal expansion of the charge density wave of EuAl2Ga2
• Room temperature charge density wave in a tetragonal polymorph of Gd2Os3Si5 and study of its origin in the RE2T3X5 (RE = Rare earth, T = transition metal, X = Si, Ge) series
• Broken inversion symmetry in the charge density wave phase in EuAl${}_4$
• Tuning Incommensurate Charge Order in Ba${}_{1-x}$Sr${}_x$Al${}_4$ and Ba${}_{1-y}$Eu${}_y$Al${}_4$