We present ab-initio phonon dispersion relations for the three lead chalcogenides PbS, PbSe, and PbTe. The acoustic branches are in very good agreement with inelastic neutron-scattering data and calculations of the specific heat give good agreement with experimental data. The pronounced minimum of the transverse optical branch at Gamma due to the near-ferroelectricity of the lead chalcogenides is qualitatively reproduced. In addition, we find a pronounced dip in the longitudinal optical branch at Gamma. This dip was previously explained as the effect of "free carriers" (due to the presence of impurities). The calculations demonstrate that it persists also in the case of pure lead chalcogenides. We explain the dip as a "near Kohn anomaly" which is associated with the small electronic band-gap at the high-symmetry point L.
Importance of Non-Adiabatic Effects on Kohn Anomalies in 1D metals
Université catholique de Louvain（天主教鲁汶大学）；Institute of Condensed Matter and Nanosciences, Université catholique de Louvain（天主教鲁汶大学凝聚态物质与纳米科学研究所）；WEL Research Institute（WEL研究所）；School of Materials Science and Engineering, Northwestern Polytechnical University（西北工业大学材料科学与工程学院）
GW quasiparticle band structures of stibnite, antimonselite, bismuthinite, and guanajuatite
采用G $_0$ W $_0$方法，对辉锑矿族的四种同结构半导体金属硫族化合物A $_2$ B $_3$（A = Sb，Bi，B = S，Se）的准粒子能带结构进行了第一性原理计算.我们进行了广泛的收敛测试，并确定准粒子的结构参数和半核心$d$电子的修正的敏感性。我们的计算表明，所有四个硫属化物表现出直接带隙，如果我们排除一些间接跃迁略低于直接间隙。相对论自旋轨道效应的Kohn-Sham能带结构进行了评估，并包括在准粒子带隙的修正。我们计算的带隙为1.5 eV（Sb $_2$ S $_3$）、1.3 eV（Sb $_2$ Se $_3$）、1.4 eV（Bi $_2$ S $_3$）和0.9 eV（Bi $_2$ Se $_3$）。通过比较我们计算的差距与理想的肖克利-奎塞尔值，我们发现，所有四个硫属化物是有前途的纳米结构的光致发光的光敏剂。
Fractional power-law behavior and its origin in iron-chalcogenide and ruthenate superconductors: Insights from first-principles calculations
我们进行现实的第一性原理计算的铁硫族化合物和铁基材料，以确定在这些系统中的洪德耦合诱导的相关性的实验签名。我们发现FeTe和KPDMATHABMM Fe $_{2-y}$ Se $_2$在它们的准粒子自能和光学电导率中显示出不寻常的轨道依赖分数幂律行为，这一现象首先在SrRuO $_3$中发现。这些材料的顺磁状态中的强不相干性导致电子状态隐藏在角度分辨光电子能谱中，其在低温下重新出现。我们确定了有效的低能量哈密顿描述这些系统，并表明这些异常是不控制的接近量子临界点，但从共存的快速量子力学轨道波动和慢自旋波动的结果。
Nonuniform grids for Brillouin zone integration and interpolation
TCM Group, Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Department of Materials Science and Metallurgy, University of Cambridge（剑桥大学材料科学与工程系）
