Browsing by Author "Mkhoyan, K. Andre"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Dopant segregation inside and outside dislocation cores in perovskite BaSnO 3 and reconstruction of the local atomic and electronic structures
    (2021-04-26) Yun, Hwanhui; Prakash, Abhinav; Birol, Turan; Jalan, Bharat; Mkhoyan, K. Andre; yunxx133@umn.edu; Yun, Hwanhui
    Distinct dopant behaviors inside and outside dislocation cores are identified by atomic-resolution electron microscopy in perovskite BaSnO3 with considerable consequences on local atomic and electronic structures. Driven by elastic strain, when A-site designated La dopants segregate near a dislocation core, the dopant atoms accumulate at the Ba sites in compressively strained regions. This triggers formation of Ba-vacancies adjacent to the core atomic sites resulting in reconstruction of the core. Notwithstanding the presence of extremely large tensile strain fields, when La atoms segregate inside the dislocation core, they become B-site dopants, replacing Sn atoms and compensating the positive charge of the core oxygen vacancies. Electron energy-loss spectroscopy shows that the local electronic structure of these dislocations changes dramatically due to segregation of the dopants inside and around the core ranging from formation of strong La-O hybridized electronic states near the conduction band minimum to insulator-to-metal transition.
  • Thumbnail Image
    Item
    Simulation of dopant atom behavior in semiconducting nanocrystals
    (2015) Duncan, Samuel J. B.; Held, Jacob; Mkhoyan, K. Andre
  • Thumbnail Image
    Item
    Strain effect on the ground-state crystal structure of Sr2SnO4 Ruddlesden-Popper oxides
    (2022-09-08) Yun, Hwanhui; Gautreau, Dominique; Mkhoyan, K. Andre; Birol, Turan; yunxx133@umn.edu; Yun, Hwanhui; Theoretical Materials Physics Group
    Simulation data for a manuscript 'Strain effect on the ground-state structure of Sr2SnO4 Ruddlesden-Popper oxides'. Key data including structures and input files for structural relaxation and phonon calculation of various phases in Sr2SnO4 are included.
  • Thumbnail Image
    Item
    Supporting data for Mending Cracks Atom-by-atom in Rutile TiO2 with Electron Beam Radiolysis
    (2023-08-28) Guo, Silu; Yun, Hwanhui; Nair, Sreejith; Jalan, Bharat; Mkhoyan, K. Andre; mkhoyan@umn.edu; Mkhoyan, K. Andre; Materials Research Science & Engineering Center
    Experimental data for a manuscript "Mending Cracks Atom-by-atom in Rutile TiO2 with Electron Beam Radiolysis". Essential data includes scanning transmission electron microscopy (STEM) raw images and electron energy-loss spectroscopy (EELS) spectrum data. Important atomic line scans data and radiolysis cross section data file are included to support our “two-step rolling” model of mobile octahedral building blocks enabling radiolysis-driven atomic migration.