Dipole Analysis of the Dielectric Function of Colour Dispersive Materials: Application to Monoclinic Ga${}_2$O${}_3$

Abstract

We apply a generalized model for the determination and analysis of the dielectric function of optically anisotropic materials with colour dispersion to phonon modes and show that it can also be generalized to excitonic polarizabilities and electronic band-band transitions. We take into account that the tensor components of the dielectric function within the cartesian coordinate system are not independent from each other but are rather projections of the polarization of dipoles oscillating along directions defined by the, non-cartesian, crystal symmetry and polarizability. The dielectric function is then composed of a series of oscillators pointing in different directions. The application of this model is exemplarily demonstrated for monoclinic ($\beta$-phase) Ga${}_2$O${}_3$ bulk single crystals. Using this model, we are able to relate electronic transitions observed in the dielectric function to atomic bond directions and orbitals in the real space crystal structure. For thin films revealing rotational domains we show that the optical biaxiality is reduced to uniaxial optical response.

10 pages, 6 figures

References in corpus (3)

• Anisotropy, phonon modes, and free charge carrier parameters in monoclinic $\beta$-gallium oxide single crystals
• Dielectric tensor of monoclinic Ga${}_2$O${}_3$ single crystals in the spectral range $0.5-8.5$eV
• Anisotropic optical properties of rhombohedral and tetragonal thin film BiFeO${}_3$ phases

Cited by in corpus (11)

• Band-to-band transitions, selection rules, effective mass and exciton binding energy parameters in monoclinic β-Ga2O3
• Structural, electronic, elastic, power and transport properties of $\beta$-Ga${}_2$O${}_3$ from first-principles
• Electron effective mass in Sn-doped monoclinic single crystal $\beta$-gallium oxide determined by mid-infrared optical Hall effect
• Role of carbon and hydrogen in limiting $n$-type doping of monoclinic (Al${}_x$Ga${}_{1-x}$)${}_2$O${}_3$
• Two-dimensional natural hyperbolic materials: From polaritons modulation to applications
• Highly asymmetric optical properties of \b{eta}-Ga2O3 as probed by linear and nonlinear optical excitation spectroscopy
• Anisotropic dielectric functions, band-to-band transitions, and critical points in α-Ga2O3
• Anisotropy and phonon modes from analysis of the dielectric function tensor and inverse dielectric function tensor of monoclinic yttrium orthosilicate
• Elevated temperature dependence of the anisotropic visible-to-ultraviolet dielectric function of monoclinic beta-Ga2O3
• Infrared active phonons in monoclinic lutetium oxyorthosilicate
• Anisotropic excitonic photocurrent in $\beta$-Ga${}_2$O${}_3$