论文标题
过渡金属Trichalcogenides NBSE $ _3 $和单斜tas $ _3 $的电子孔响应函数NBSE $ _3 $
Electron-hole response function of transition metal trichalcogenides NbSe$_3$ and monoclinic-TaS$_3$
论文作者
论文摘要
nbse $ _3 $和单斜tas $ _3 $（$ m $ -tas $ _3 $）是准1D金属，其中包含三种不同类型的链条，并且在T $ _ {p_1} $ {p_1} $ {p_1} $ and T $ _ {p_2} $ _ {p_1} $ _ {p_1} $ _ {p_2} $的PEIERLS PEIERLS过渡时进行了两个不同的电荷密度波（CDW）。这些跃迁的性质是根据其电子孔林德哈德响应函数的第一原理DFT计算讨论的。由于链间相互作用更强，NBSE $ _3 $的费米表面（FS）和Lindhard功能比$ M $ -M $ -TAS $ _3 $复杂得多；但是，可以提出一个常见的情况来合理化结果。链内带间嵌套过程主导了两种化合物的I型和III型链的最强响应。在（0 $ a $*，0 $ c $*）和（1/2 $ a $*，1/2 $ c $*）t $ _ {p_1} $ _ {p_2} $的情况下，在lindhard $ _3 $上定义了两个定义明确的最大响应。 t $ _ {p2} $。对不同链间耦合机制的分析得出的结论是，FS嵌套效应仅与将NBSE $ _3 $的横向$*组件设置为$*组件有关。对于沿NBSE $ _3 $中的$ c $*的横向耦合，以及$ a $*和$ c $*的$ m $ -tas $ -tas $ _3 $，必须考虑到最强的链链库仑耦合机制。声子频谱计算显示巨型2 $ k_f $ kohn Anomaly的形成$ m $ -tas $ _3 $。所有这些结果都支持了过渡金属三卡构基化的PEIERLS过渡的弱耦合方案。
NbSe$_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.
