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The nonzero thickness of single-layer (SL) MoS2 manifests in electron states forming classes of states that are even and odd with respect to reflections through the central plane. These states are energetically well separated: In particular, we show that pristine SL MoS2 exhibits two band gaps, Eg∥ = 1.9 eV and Eg⊥ = 3.2 eV, for the optical in-plane and out-of-plane susceptibilities χ∥ and χg⊥. respectively. Because of this, odd states are often neglected, which effectively reduces SL MoS2 to a perfect two-dimensional system. We study states bound to defects in SL MoS2 with three types of vacancy defects (VDs), (i) Mo vacancy, (ii) S2 vacancy, and (iii) 3 × MoS2 quantum antidot, and show that odd states play an equally important role as the even states. In particular, we show that odd states bound to VDs lead to resonances in χg⊥ inside Eg⊥ in SL MoS2 with VDs. Additionally, we demonstrate that the states bound to VDs are not necessarily confined to the band gap in the even subsystem, which necessitates extending the energy region affected by the bound states. [ABSTRACT FROM AUTHOR]

Over the past decade, the open frame ("cagey") structure of CoSb3 skutterudite has invited intensive filling studies with various rare-earth elements for delivering state-of-the-art midtemperature thermoelectric performance. To rationalize previously reported experimental results and provide new insight into the underexplored roles of La fillers and Sb vacancies, ab initio density functional theory studies, along with semiclassical Boltzmann transport theory calculations, are performed for pristine CoSb3 of different lattice settings and La-filled CoSb3 with and without Sb's mono- and divacancy defects. The effects of spin-orbit coupling (SOC), partial La filling, Sb vacancy defects, and spin polarization on the electronic and thermoelectric properties are systematically examined. The SOC shows minor effects on the electronic and thermoelectric properties of CoSb3. The peculiar quasi-Dirac band in the pristine CoSb3 largely survives La filling but not Sb vacancies, which instead introduce dispersive bands in the band gap region. The non-spin-polarized and spin-polarized solutions of La-filled CoSb3 are nearly degenerate. Importantly, the band structure, density of states, and Fermi surface of the latter are significantly spin polarized, giving rise to spin-dependent thermoelectric properties. Seebeck coefficients directly calculated as a function of chemical potential are interpreted in connection with the electronic structures. Temperature-dependent Seebeck coefficients derived for the experimentally studied materials agree well with available experimental data. Seebeck coefficients obtained as a function of charge carrier concentration corroborate the thermoelectrically favorable role at high filling fractions played by the Fermi electron pockets associated with the degenerate valleys in the conduction bands, and also point toward a similar role of the Fermi hole pockets associated with the degenerate hills in the valence bands. These results serve to advance the understanding of CoSb3 skutterudite, a class of materials with important fundamental and application implications for thermoelectrics and spintronics. [ABSTRACT FROM AUTHOR]

Suezawa et al. [Phys. Rev. B 90, 117201 (2014)] claim in their Comment that the data reported by Shimizu et al. [Phys. Rev. Lett. 98, 095901 (2007)] and Kube et al. [Phys. Rev. B 88, 085206 (2013)] on silicon selfdiffusion for temperatures between 900 and 735 °C are affected by carbon and vacancy clusters and, accordingly, do not reflect self-diffusion under thermal equilibrium conditions. We demonstrate in our Reply that an impact of carbon on self-diffusion can definitely be excluded. In addition it is rather unlikely that the self-diffusion data reported by Shimizu et al. [Phys. Rev. Lett. 98, 095901 (2007)] and Kube et al. [Phys. Rev. B 88.085206 (2013)] are affected by the dissolution of vacancy clusters since strong differences exist not only in the preparation of the samples used for the experiments, but also in the time of diffusion. Finally, the vacancy formation enthalpy deduced by Suezawa et al. [J. Appl. Phys. 110, 083531 (2011)] from quenching experiments is consistent with the value obtained from the temperature dependence of the vacancy formation enthalpy reported by Kube et al. [Phys. Rev. B 88, 085206 (2013)]. Overall we conclude that the quenching experiments of Suezawa et al. [J. Appl. Phys. 110, 083531 (2011)] cannot disprove the interpretation of the low-temperature self-diffusion data reported by Shimizu etal. [Phys. Rev. Lett. 98,095901 (2007)] and Kube et al. [Phys. Rev. B 88, 085206 (2013)]. [ABSTRACT FROM AUTHOR]