过渡金属三硫族化合物NbSe $_3$和monoclinic-TaS $_3$的电子空穴响应函数
Electron-hole response function of transition metal trichalcogenides NbSe$_3$ and monoclinic-TaS$_3$
摘要：
NbSe $_3$和单斜-TaS $_3$（$m$ -TaS $_3$）是准一维金属，含有三种不同类型的链，在T $_{P_1}$和T $_{P_2}$发生两种不同的电荷密度波（CDW）Peierls跃迁。在第一性原理DFT计算电子-空穴Lindhard响应函数的基础上讨论了这些跃迁的性质。由于更强的链间相互作用，NbSe $_3$的费米面（FS）和林哈德函数比$m$ $_3$的费米面和林哈德函数复杂得多;然而，可以提出一种常见的方案来合理化结果。两种化合物的I型和III型链的链内带间嵌套过程占主导地位的最强响应。在T $_{P_1}$和T $_{P_2}$处分别发现NbSe $_3$的Lindhard响应的两个明确定义的最大值（0 $a$ *，0 $c$ *）和（1/2 $a$ *，1/2 $c$ *）横向分量，而在T $_{P2}$处未观察到$m$ -TaS $_3$的第二个最大值。不同的链间耦合机制的分析导致的结论，FS嵌套效应仅与设置横向$a$ * 组件在NbSe $_3$。对于在NbSe $_3$中沿着$c$ * 以及对于$m$ $_3$沿着$a$ * 和$c$ * 的横向耦合，必须考虑最强的链间库仑耦合机制。声子谱计算表明在$m$ -TaS $_3$中形成了巨大的2 $k_F$ Kohn反常.这些结果支持了过渡金属硫属化合物Peierls跃迁的弱耦合假设。
英文摘要：
NbSe$_3$ and monoclinic-TaS$_3$ ($m$-TaS$_3$) are quasi-1D metals containing three different types of chains and undergoing two different charge density wave (CDW) Peierls transitions at T$_{P_1}$ and T$_{P_2}$. The nature of these transitions is discussed on the basis of first-principles DFT calculation of their electron-hole Lindhard response function. As a result of stronger inter-chain interactions the Fermi surface (FS) and Lindhard function of NbSe$_3$ are considerably more complex than those for $m$-TaS$_3$; however a common scenario can be put forward to rationalize the results. The intra-chain inter-band nesting processes dominate the strongest response for both type I and type III chains of the two compounds. Two well-defined maxima of the Lindhard response for NbSe$_3$ are found with the (0$a$*, 0$c$*) and (1/2$a$*, 1/2$c$*) transverse components at T$_{P_1}$ and T$_{P_2}$, respectively, whereas the second maximum is not observed for $m$-TaS$_3$ at T$_{P2}$. Analysis of the different inter-chain coupling mechanisms leads to the conclusion that FS nesting effects are only relevant to set the transverse $a$* components in NbSe$_3$. For the transverse coupling along $c$* in NbSe$_3$ and along both $a$* and $c$* for $m$-TaS$_3$, one must take into account the strongest inter-chain Coulomb coupling mechanism. Phonon spectrum calculations show the formation of a giant 2$k_F$ Kohn anomaly in $m$-TaS$_3$. All these results support the weak coupling scenario for the Peierls transition of transition metal trichalcogenides.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
