Joint Meeting of the Four Corners and Texas Sections of the American Physical Society
Volume 61, Number 15
Friday–Saturday, October 21–22, 2016;
Las Cruces, New Mexico
Session C2: Materials Science I
1:00 PM–2:24 PM,
Friday, October 21, 2016
Room: Ballroom 2
Chair: Anna Zaniewski, Arizona State University
Abstract ID: BAPS.2016.TSF.C2.1
Abstract: C2.00001 : Phase transformations in transition metal oxides for electronic device applications
1:00 PM–1:24 PM
Preview Abstract
Abstract
Author:
Alexander Demkov
(The University of Texas)
Transition metal oxides (TMO) are currently used in a variety of electronic
devices and have been considered for a number of emergent technologies. The
unfilled d-shells of transition metals are responsible for many unusual
properties of these oxides and in particular, a multitude of phase
transitions that range from structural to electronic. The recently developed
ability to grow layers of TMOs with the atomic precision by means of
physical vapor deposition has led to discovery of many fascinating phenomena
that cannot be easily realized in bulk materials and to integration of these
oxides on semiconductors.
In this talk I will review briefly the ferroic ordering and
metal-to-insulator transition in TMOs focusing primarily on the Peierls
transition in NbO$_{\mathrm{2}}$. I will discuss the basic properties of
NbO$_{\mathrm{2}}$ and our efforts in growing single crystal
NbO$_{\mathrm{2}}$ on several oxide substrates. For practical applications
relying on the metal-to-insulator transition, the band gap and phase purity
of the material are of key importance. I will discuss our present
understanding of the electronic structure of the low-temperature insulating
phase of NbO$_{\mathrm{2}}$, which is based on photoemission spectroscopy,
spectroscopic ellipsometry and density functional theory [1-3]. I will also
explain how to distinguish under-oxidized and over-oxidized phases using a
combination of first principles modeling with the core-level and valence
band spectroscopy [4].\\
\\[1] B. Posadas, A. O'Hara, S. Rangan, R. A. Bartynski, and A. A. Demkov,
"Band gap of epitaxial in-plane-dimerized single-phase NbO$_{\mathrm{2}}$
films," Appl. Phys. Lett. \textbf{104}, 092901 (2014).
[2] A. O'Hara, T. N. Nunley, A. B. Posadas, S. Zollner, and A. A. Demkov,
``Electronic and optical properties of NbO$_{\mathrm{2}}$,'' J. Appl. Phys.
\textbf{116}, 213705 (2014).
[3] A. O'Hara and A. A. Demkov, ``The nature of the metal-insulator
transition in NbO$_{\mathrm{2}}$,'' Phys. Rev. B \textbf{91}, 094305 (2015).
[4] T. Hadamek, A. B. Posadas, A. Dhamdhere, A. J. Smith and A. A. Demkov,
``Spectral identification scheme for epitaxially-grown single-phase niobium
dioxide,'' J. Appl. Phys., \textbf{119}, 095308 (2016)\textbf{\textit{.}}
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2016.TSF.C2.1