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In this paper, the electronic structure and transport properties of a ductile thermoelectric material α-Ag2S are examined using first-principles calculations combined with the Boltzmann transport equation within a constant relaxation-time approximation. The use of the exchange–correlation functional SCAN + rVV10 successfully describes the geometric and electronic structure of α-Ag2S with a direct bandgap value of 0.99 eV, which is consistent with the previous experimental observations. Based on the calculations of the formation energy of typical intrinsic defects, it is found that intrinsic defect formation greatly affects the conductivity of the system where silver vacancy and interstitial silver act as p-type and n-type defects, respectively. Large Seebeck coefficients at room-temperature, of around −760 μV K−1 for n-type and 1400 μV K−1 for p-type, are realized. It is also suggested that the doping of fully filled d-block elements such as Cu and Au not only maintained the Seebeck coefficients at high values but also improved electrical conductivity by more than 1.4 times, leading to the improvement of the power factor by up to 40% compared to the non-doped sample at low carrier concentration. [ABSTRACT FROM AUTHOR]

Correction for 'Intrinsic defect formation and the effect of transition metal doping on transport properties in a ductile thermoelectric material α-Ag2S: a first-principles study' by Ho Ngoc Nam et al., Phys. Chem. Chem. Phys., 2021, DOI: 10.1039/d0cp06624a. [ABSTRACT FROM AUTHOR]

In this work, we calculated physical quantities, including the magnetocrystalline anisotropy constant ( K u ) and magnetization ( M s ), for disordered (Ce,La)(Co,Fe) 5 systems. Based on the results, we propose CeCo 4.7 Fe 0.3 as the optimum composition for high-performance permanent magnets. The calculations employed the full-potential Korringa-Kohn-Rostoker Green's function method, and dealt with the compositional disorder of the systems within the coherent potential approximation. It was found that the La doping reduces K u at 0 K but increases the Curie temperature ( T C ), which leads to improvement of the magnetic properties at high temperatures. CeCo 4.7 Fe 0.3 had the largest magnetic anisotropy of K u = 15.14 MJ/m 3 , which is larger than that of CeCo 5 ( K u = 14.77 MJ/m 3 ). T C of CeCo 4.7 Fe 0.3 estimated by the mean-field approximation was 1005 K, which exceeds that of CeCo 5 (965 K). Further, our calculations showed that while doping of Fe destabilizes the system, CeCo 4.7 Fe 0.3 is stable against decomposition into the simple substances. We also show calculated data that are informative for exploring high-performance permanent magnet materials in this paper., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

In this paper, the electronic structure and transport properties of a ductile thermoelectric material α-Ag2S are examined using first-principles calculations combined with the Boltzmann transport equation within a constant relaxation-time approximation. The use of the exchange-correlation functional SCAN + rVV10 successfully describes the geometric and electronic structure of α-Ag2S with a direct bandgap value of 0.99 eV, which is consistent with the previous experimental observations. Based on the calculations of the formation energy of typical intrinsic defects, it is found that intrinsic defect formation greatly affects the conductivity of the system where silver vacancy and interstitial silver act as p-type and n-type defects, respectively. Large Seebeck coefficients at room-temperature, of around -760 μV K-1 for n-type and 1400 μV K-1 for p-type, are realized. It is also suggested that the doping of fully filled d-block elements such as Cu and Au not only maintained the Seebeck coefficients at high values but also improved electrical conductivity by more than 1.4 times, leading to the improvement of the power factor by up to 40% compared to the non-doped sample at low carrier concentration.

Correction for 'Intrinsic defect formation and the effect of transition metal doping on transport properties in a ductile thermoelectric material α-Ag 2 S: a first-principles study' by Ho Ngoc Nam et al., Phys. Chem. Chem. Phys., 2021, DOI: .