Effects of "stuffing" on the atomic and electronic structure of the pyrochlore Yb${}_2$Ti${}_2$O${}_7$

Abstract

There are reasons to believe that the ground state of the magnetic rare earth pyrochlore Yb${}_2$Ti${}_2$O${}_7$ is on the boundary between competing ground states. We have carried out $\text{ab initio}$ density functional calculations to determine the most stable chemical formula as a function of the oxygen chemical potential and the likely location of the oxygen atoms in the unit cell of the "stuffed" system. We find that it is energetically favorable in the "stuffed" crystal (with an Yb replacement on a Ti site) to contain oxygen vacancies which dope the Yb 4$\text{f}$ orbitals and qualitatively change the electronic properties of the system. In addition, with the inclusion of the contribution of spin-orbit-coupling (SOC) on top of the GGA+U approach, we investigated the electronic structure and the magnetic moments of the most stable "stuffed" system. In our determined "stuffed" structure the valence bands as compared to those of the pure system are pushed down and a change in hybridization between the O 2$\text{p}$ orbitals and the metal ion states is found. Our first-principle findings should form a foundation for effective models describing the low-temperature properties of this material whose true ground state remains controversial.

6 pages, 5 figures

References in corpus (11)

• Quasiparticle band structure based on a generalized Kohn-Sham scheme
• Lightly stuffed pyrochlore structure of single-crystalline Yb2Ti2O7 grown by the optical floating zone technique
• Is the Yb2Ti2O7 pyrochlore a quantum spin ice?
• Quasiparticle Breakdown and Spin Hamiltonian of the Frustrated Quantum Pyrochlore Yb${}_2$Ti${}_2$O${}_7$ in Magnetic Field
• Impact of Stoichiometry of Yb2Ti2O7 on its Physical Properties
• Quantum spin configurations in Tb2Ti2O7
• Reentrant Phase Diagram of $\mathrm{Y}{\mathrm{b}}_2\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_7$ in $⟨111⟩$ Magnetic Field
• Ising Like Order by Disorder In The Pyrochlore Antiferromagnet with Dzyaloshinskii-Moriya Interactions
• Dilute stuffing in the pyrochlore iridate $E{u}_{2}I{r}_2{O}_7$
• Magnetic Excitations in the Ground State of $\mathrm{Y}{\mathrm{b}}_2\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_7$
• Crystal field excitations from $\mathrm{Y}{\mathrm{b}}^{3+}$ ions at defective sites in highly stuffed $\mathrm{Y}{\mathrm{b}}_2\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_7$

Cited by in corpus (5)

• Role of defects in determining the magnetic ground state of ytterbium titanate
• Dilute stuffing in the pyrochlore iridate $E{u}_{2}I{r}_2{O}_7$
• Crystal field excitations from $\mathrm{Y}{\mathrm{b}}^{3+}$ ions at defective sites in highly stuffed $\mathrm{Y}{\mathrm{b}}_2\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_7$
• Orientation Dependence of the Magnetic Phase Diagram of Yb${}_2$Ti${}_2$O${}_7$
• Localized Triplons and Site Stuffing in the Quantum Dimer Magnet BiYbGeO${}_5$