References of "Nugraha, A.R.T"
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See detailThermoelectric properties of two-dimensional hydrogenated borophene: A first-principles study
Hanna, M.Y.; Hasdeo, Eddwi Hesky UL; Suprayoga, E. et al

in AIP Conference Proceedings (2020), 2256(1), 030017

We theoretically study electronic and thermoelectric properties of two-dimensional hydrogenated borophene (”boro-phane”). We show that, according to the first-principles calculation, hydrogenated ... [more ▼]

We theoretically study electronic and thermoelectric properties of two-dimensional hydrogenated borophene (”boro-phane”). We show that, according to the first-principles calculation, hydrogenated borophene is semimetallic, with two bands meeting at a single point at the Fermi level. The thermoelectric properties evaluated by using the Boltzmann equation with a constant relaxation time approximation (CRTA). At room temperature, we obtain large power factor for electron doping regime. Therefore, appropriate doping to this material can enhance its thermoelectric efficiency. [less ▲]

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See detailAb-initio calculation of muon spin polarization function to study lithium-ion diffusion in LiTi2O4 battery material
Suprayoga, E.; Rifai, A.; Subhan, A. et al

in AIP Conference Proceedings (2020), 2256(1), 030015

We report the study of lithium-ion diffusion in LiTi2O4 battery material by the analysis of muon spin polarization function at the muon site by DFT calculation. The important parameters which explain the ... [more ▼]

We report the study of lithium-ion diffusion in LiTi2O4 battery material by the analysis of muon spin polarization function at the muon site by DFT calculation. The important parameters which explain the lithium-ion diffusion will be derived from the function, including the field fluctuation rate and the local field distribution. The calculated results are shown in good agreement with the previously measured field distribution and the field fluctuation rate in LiTi2O4 at the ground state temperature. This method, therefore, may apply to the study of other battery materials. [less ▲]

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See detailThermoelectric properties of Mexican-hat band structures
Nurhuda, M; Nugraha, ART; Hanna, MY et al

in Advances in Natural Sciences: Nanoscience and Nanotechnology (2020), 11(1), 015012

Materials with Mexican-hat electronic energy dispersions emerging from heterostructures, substrate effects, or spin–orbit couplings are believed to exhibit excellent thermoelectric properties due to its ... [more ▼]

Materials with Mexican-hat electronic energy dispersions emerging from heterostructures, substrate effects, or spin–orbit couplings are believed to exhibit excellent thermoelectric properties due to its van Hove singularity of density of states in two-dimension. However, within a constant relaxation time approximation, we disprove this belief and we find that the singularity effect is cancelled down by the group velocity contribution in the thermoelectric transport distribution. Nevertheless, the band parameters can still be optimised to reach thermoelectric figure of merit larger than 2 in a wide bandwidth, thus keeping the potential of materials with Mexican-hat bands for thermoelectric applications. [less ▲]

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See detailThermoelectric properties of Mexican-hat band structures
Nurhuda, M; Nugraha, ART; Hanna, MY et al

in Advances in Natural Sciences: Nanoscience and Nanotechnology (2020), 11(1), 015012

Materials with Mexican-hat electronic energy dispersions emerging from heterostructures, substrate effects, or spin–orbit couplings are believed to exhibit excellent thermoelectric properties due to its ... [more ▼]

Materials with Mexican-hat electronic energy dispersions emerging from heterostructures, substrate effects, or spin–orbit couplings are believed to exhibit excellent thermoelectric properties due to its van Hove singularity of density of states in two-dimension. However, within a constant relaxation time approximation, we disprove this belief and we find that the singularity effect is cancelled down by the group velocity contribution in the thermoelectric transport distribution. Nevertheless, the band parameters can still be optimised to reach thermoelectric figure of merit larger than 2 in a wide bandwidth, thus keeping the potential of materials with Mexican-hat bands for thermoelectric applications. [less ▲]

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See detailCharacterization of electron and phonon transports in Bi-doped CaMnO3 for thermoelectric applications
Suprayoga, E; Putri, WBK; Singsoog, K et al

in arXiv (2020)

Electron and phonon transports in CaMnO3 and its Bi-doped counterpart, Bi0. 03Ca0. 97MnO3, are investigated by thermoelectric transport measurements, Raman spectroscopy, and first-principles calculations ... [more ▼]

Electron and phonon transports in CaMnO3 and its Bi-doped counterpart, Bi0. 03Ca0. 97MnO3, are investigated by thermoelectric transport measurements, Raman spectroscopy, and first-principles calculations. In particular, we focus on CaMnO3 and Bi0. 03Ca0. 97MnO3's electronic structures, temperature-dependent electron and phonon lifetimes, and their sound velocities. We find that the anti-ferromagnetic insulator CaMnO3 breaks the Wiedemann-Franz (WF) law with the Lorenz number reaching four times that of ordinary metals at room temperature. Bismuth doping reduces both the electrical resistivity and the Seebeck coefficient of CaMnO3, thus it recovers the WF law behavior. Raman spectroscopy confirms that Bi0. 03Ca0. 97MnO3 has a lower Debye frequency as well as a shorter phonon lifetime. As a result, Bi0. 03Ca0. 97MnO3 exhibits superior thermoelectric properties over the pristine CaMnO3 due to the lower thermal conductivity and electronic resistivity. [less ▲]

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