论文标题
$^{57} $ fe取代基的Mössbauer参数$ bi_2se_3 $
Mössbauer parameters of $^{57}$Fe substituents in the topological insulator $Bi_2Se_3$
论文作者
论文摘要
$^{57} $feMössbauer光谱可以探测含Fe的系统的几种\ emph {local}结构，电子和磁性。但是，要在这些属性与系统的几何结构之间建立直接关系，需要分析实验性的Mössbauer参数\ emph {via}电子结构计算。在拓扑绝缘子中，铁取代基的结构，电子和磁性效应$ bi_2se_3 $，如$^{57} $feMössbauer光谱所唯一探测的，通过} \ emph {via emph {via emph {via emph {via} spin极极化的电子结构计算。 \ emph {nominal} fe $^{3+}（s = 5/2）$氧化和旋转状态的铁离子取代基被明确证明，可以代替bi $^{3+} $ sites in Edecepaigial $ bi_2se_3 $ thin-Films中的bi $^{3+} $。与铁取代的伴随，\ emph {局部}结构重排发生，因此，本机系统的较长的BI-SE键被含有Fe的系统中的Fe-Se对应物明显较短。产生的扭曲 - 二十二叶肉质环境对取代铁离子产生了特征性的Mössbauer参数（$δ_{fe} \约$ 0.51 mm/s，$Δe_{q} \ $ 0.20 mm/s），大约$ 0.20 mm/s）与fe-doped $ bi_2se_的值相吻合，这些均与fe-doped $ bi_2se_3 $ tin $ thin collection consection。 Consistent with a substituent Fe$^{3+}$ ion's \emph{nominal} high-spin electronic configuration ($t_{2g}^{\uparrow \uparrow \uparrow} e_g^{\uparrow \uparrow}$), an Fe-centered spin density has been established which, nevertheless, extends towards neighboring Se atoms \ emph {via}直接fe-se键和伴随的fe（d）-Se（p）杂交。
$^{57}$Fe Mössbauer spectroscopy can probe several \emph{local} structural, electronic and magnetic properties of Fe-containing systems. However, to establish a direct relationship between these properties and a system's geometric structure, the experimental Mössbauer parameters need to be analyzed \emph{via} electronic structure calculations. Herein, structural, electronic and magnetic effects of iron substituents in the topological insulator $Bi_2Se_3$, as uniquely probed by $^{57}$Fe Mössbauer spectroscopy, have been determined \emph{via} spin-polarized electronic structure calculations. The iron ion substituents, of \emph{nominal} Fe$^{3+}(S = 5/2)$ oxidation and spin state, are unequivocally shown to substitute Bi$^{3+}$ sites in epitaxial $Bi_2Se_3$ thin-films used for Mössbauer measurements. Concomitant with iron substitution, \emph{localized} structural rearrangements take place whereby the longer Bi-Se bonds of the native system are replaced by significantly shorter Fe-Se counterparts in the Fe-containing system. The resulting distorted-octahedral environment about substituent iron ions gives rise to characteristic Mössbauer parameters ($δ_{Fe} \approx$ 0.51 mm/s, $ΔE_{Q} \approx$ 0.20 mm/s) which have been calculated in excellent agreement with measured values for Fe-doped $Bi_2Se_3$ thin films. Consistent with a substituent Fe$^{3+}$ ion's \emph{nominal} high-spin electronic configuration ($t_{2g}^{\uparrow \uparrow \uparrow} e_g^{\uparrow \uparrow}$), an Fe-centered spin density has been established which, nevertheless, extends towards neighboring Se atoms \emph{via} direct Fe-Se bonding and concomitant Fe(d)-Se(p) hybridization.
