Ruchika Mahajan
(Indian Institute of Technology Mandi, India)

In this talk, I will present structural, electronic, and magnetic properties of pyrolusite (β- MnO₂) using conventional and extended Hubbard-corrected density-functional theory (DFT+U and DFT+U+V) using first principles. The onsite U and intersite V Hubbard parameters are computed using linear-response theory in the framework of density- functional perturbation theory ^[1][2]. In this study, we have shown that inclusion of the onsite U is crucial to describe the localized nature of the Mn(3d) states, whereas intersite V is key to capture accurately the strong hybridization between neighboring Mn(3d) and O(2p) states. In this framework, we stabilize the simplified collinear antiferromagnetic (AFM) ordering in β-MnO₂ (suggested by the Goodenough-Kanamori rule) ^[3] that is commonly used as an approximation to the experimentally observed noncollinear screw-type spiral magnetic ordering ^[4]. Finally, we will discuss the results of β-MnO₂ from Hubbard- corrected DFT using two kinds of Hubbard manifolds—non-orthogonalized and orthogonalized atomic orbitals for ferromagnetic and its other three collinear spin configurations ^[5].



_{^[1] I. Timrov, N. Marzari, and M. Cococcioni, Phys. Rev. B 98, 085127 (2018)
^[2] I. Timrov, N. Marzari, and M. Cococcioni, Phys. Rev. B 103, 045141 (2021)
^[3] Phys.Chem.Chem.Phys., 2016, 18, 13294
^[4] A. Yoshimori, J. Phys. Soc. Japan 14, 807 (1959)
^[5] Ruchika Mahajan, Iurii Timrov, Nicola Marzari, and Arti Kashyap, Phys. Rev. Materials 5, 104402 (2021)}



 

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