Flat bands in ultra-wide gap two-dimensional germanium dioxide

Rafael Franco Ribeiro Reis; Gabriel Elyas Gama Araujo; Danilo Kuritza; Alexandre Cavalheiro Dias; Andreia Luisa da Rosa; Renato Borges Pontes

arXiv · 2510.24685

Flat bands in ultra-wide gap two-dimensional germanium dioxide

Rafael Franco Ribeiro Reis·Gabriel Elyas Gama Araujo·Danilo Kuritza·Alexandre Cavalheiro Dias·Andreia Luisa da Rosa·Renato Borges Pontes

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Abstract

We employ first principles density-functional theory (DFT) and the Bethe-Salpeter equation (BSE) in the framework of tight-binding based maximally localized Wannier functions (MLWF-TB) model to investigate the electronic and optical properties of free-standing two-dimensional (2D) germanium dioxide phases. All investigated 2D GeO2 polymorphs exhibit ultra-wide band gaps and strong excitonic effects, with flat O-p-derived valence bands tunable under strain. These features allow the design of flat band materials with ultra large electronic gaps in low-dimensional systems, making these materials promising for devices operation at higher voltages and temperatures than conventional semiconductor materials.

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Rafael Franco Ribeiro Reis, Gabriel Elyas Gama Araujo, Danilo Kuritza, Alexandre Cavalheiro Dias, Andreia Luisa da Rosa, Renato Borges Pontes. 2025-10-28. Flat bands in ultra-wide gap two-dimensional germanium dioxide. https://arxiv.org/abs/2510.24685

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