We develop a systematic typical medium dynamical cluster approximation that provides a proper description of the Anderson localization transition in three dimensions (3D). Our method successfully captures the localization phenomenon both in the low a
nd large disorder regimes, and allows us to study the localization in different momenta cells, which renders the discovery that the Anderson localization transition occurs in a cell-selective fashion. As a function of cluster size, our method systematically recovers the re-entrance behavior of the mobility edge and obtains the correct critical disorder strength for Anderson localization in 3D.
We report both experimental and theoretical investigations of the physical properties of Ba$_mathrm{2}$Mn$_mathrm{2}$Sb$_mathrm{2}$O single crystals. This material exhibits a hexagonal structure with lattice constants: a = 4.7029(15) AA{} and c = 19.
9401(27) AA{}, as obtained from powder X-ray diffraction measurements, and in agreement with structural optimization through density functional theory (DFT) calculations. The magnetic susceptibility and specific heat show anomalies at T$_mathrm{N}$ = 60 K, consistent with antiferromagnetic ordering. However, the magnitude of T$_mathrm{N}$ is significantly smaller than the Curie-Weiss temperature ($mid$$mathrm{Theta_{CW}}$$mid$ $approx$ 560 K), suggesting a magnetic system of reduced dimensionality. The temperature dependence of both the in-plane and out-of-plane resistivity changes from an activated at $T$ $>$ T$_mathrm{x}$ $sim$ 200 K to a logarithmic at $T$ $<$ T$_mathrm{x}$. Correspondingly, the magnetic susceptibility displays a bump at T$_mathrm{x}$. DFT calculations at the DFT + U level support the experimental observation of an antiferromagnetic ground state.
We report a first-principles Wannier function study of the electronic structure of PdTe. Its electronic structure is found to be a broad three-dimensional Fermi surface with highly reduced correlations effects. In addition, the higher filling of the
Pd $d$-shell, its stronger covalency resulting from the closer energy of the Pd-$d$ and Te-$p$ shells, and the larger crystal field effects of the Pd ion due to its near octahedral coordination all serve to weaken significantly electronic correlations in the particle-hole (spin, charge, and orbital) channel. In comparison to the Fe Chalcogenide e.g., FeSe, we highlight the essential features (quasi-two-dimensionality, proximity to half-filling, weaker covalency, and higher orbital degeneracy) of Fe-based high-temperature superconductors.
