Hidden Structural Order in Orthorhombic Tantalum Pentoxide (Ta${}_2$O${}_5$)

Abstract

We investigate using first-principles calculations the atomic structure of the orthorhombic phase of Ta${}_2$O${}_5$. Although this structure has been studied for decades, the correct structural model is controversial owing to the complication of structural disorder. We identify a new low-energy high-symmetry structural model where all Ta and O atoms have correct formal oxidation states of +5 and -2, respectively, and the experimentally reported triangular lattice symmetry of the Ta sublattice appears dynamically at finite temperatures. To understand the complex atomic structure of the Ta${}_2$O${}_3$ plane, a triangular graph-paper representation is devised and used alongside oxidation state analysis to reveal infinite variations of the low-energy structural model. The structural disorder of Ta${}_2$O${}_5$ observed in experiments is attributed to the intrinsic structural variations, and oxygen vacancies that drive collective relaxation of the O sublattice.

5 pages, 3 figures

Cited by in corpus (16)

• Prediction of New Ground State Crystal Structure of Ta2O5
• Evidence for structural transition in crystalline tantalum pentoxide films grown by RF magnetron sputtering
• Evolutionary optimization of a charge transfer ionic potential model for Ta/Ta-oxide hetero-interfaces
• Effect of Ion Bombardment on the Chemical Properties of Crystalline Tantalum Pentoxide Films
• Ab initio simulation of $\mathrm{T}{\mathrm{a}}_2{\mathrm{O}}_5$: A high symmetry ground state phase with application to interface calculation
• Influence of post-deposition annealing on the chemical states of crystalline tantalum pentoxide films
• Structural and Electronic Properties of Ta2O5 with One Formula Unit
• Analytical Modelling of the Transport in Analog Filamentary Conductive-Metal-Oxide/HfOx ReRAM Devices
• Unsupervised learning-based structural analysis: Search for a characteristic low-dimensional space by local structures in atomistic simulations
• The electronic structures of TiO2/Ti4O7, Ta2O5/TaO2 interfaces and the interfacial effects of dopants
• Electronic Structure of Ta${}_2$O${}_5$ Polymorphs: Variation Trend of Band Gap and the Role of Oxygen Vacancies
• An atomically thin oxide layer on the elemental superconductor Ta(001) surface
• Deep insights into the local structure of amorphous Ta2O5 thin films by X-ray pair distribution function analysis
• Suppressed paramagnetism in amorphous Ta${}_2$O${}_{5-x}$ oxides and its link to superconducting qubit performance
• The role of single oxygen or metal induced defect and correlated multiple defects in the formation of conducting filaments
• Ab initio Phase Diagram of Ta2O5