Consideration of the validity of the 14 valence electron rule for semiconducting chimney-ladder phase compounds

Solution Growth and Thermoelectric Properties of Single-Phase MnSi1.75−x

“…Below 300 K, the resistivity decreases with decreasing temperature. This metallic behavior is consistent with the theoretical prediction that Mn 11 Si 19 is a degenerate p-type semiconductor, 4,5 and is similar to the behavior in previous results measured on melt-grown HMS crystals. 2,9,11,[17][18][19] Given that the detected Hall voltage is as low as the detection limit of our Hall measurement system, we cannot determine the carrier concentration at this moment.…”

“…1,2 The natural abundance of the constituent elements and their low toxicity make HMSs suitable for use in large-scale thermoelectric power generation and as a human-friendly thermoelectric power source for consumer use. 3 Given that the energy gaps of HMSs (0.6 eV to 0.8 eV) [4][5][6] are close to those of Mg 2 Si (0.66 eV), 7,8 and that their Fermi levels lie near the valence band, HMSs are very attractive as p-type thermoelectric materials used with an n-type magnesium silicide thermoelectric material. 1,2,9,10 There are four different tetragonal phases for the MnSi 1.75Àx formula, including Mn 4 Si 7 , 11 Mn 11 Si 19 , 12,13 Mn 15 Si 26 , 14 and Mn 27 Si 47 15 (Table I).…”

“…4 Nevertheless, the latter phases can also be treated as degenerate p-type semiconductors because the Fermi level is partly inside the valence band. 4,5 Considering the recent progress on understanding their electronic structure, phase control of HMSs is tremendously important for understanding the basic properties of these materials and their thermoelectric applications.…”

Electronic structures of platinum group elements silicides calculated by a first-principle pseudopotential method using plane-wave basis

“…Though these reports describe their experimental behaviors, their electronic structures have not been calculated except for OsSi 2 [10], Ru 2 Si 3 and Os 2 Si 3 [11][12][13]. In the present paper, * Corresponding author.…”

“…Calculation methods are the same as those used in the previous studies [13][14][15][16]. That is, the code of CASTEP (Cambride Serial Total Energy Package) [17] has been used, which is a first-principle pseudopotential method based on the density-functional theory (DFT) for describing the electron-electron interaction, a pseudopotential description of the electron-core interaction, and a plane-wave expansion of the wavefunctions.…”