Subtle effect of doping on the charge density wave in TaTe2-delta (delta=0.028-0.123) crystals revealed by anisotropic transport measurements and Raman spectroscopy
Subtle effect of doping on the charge density wave in TaTe2-delta (delta=0.028-0.123) crystals revealed by anisotropic transport measurements and Raman spectroscopy
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各向异性输运测量和拉曼光谱揭示了掺杂对 TaTe2-delta (delta=0.028-0.123) 晶体中电荷密度波的微妙影响
DOI：
10.1103/physrevb.103.064103
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发表时间：
2021
影响因子：
3.7
通讯作者：
Chen Yan-Feng
中科院分区：
文献类型：
--
作者：
Luo Ye-Cheng;Lv Yang-Yang;Zhang Rui-Ming;Xu Lu;Zhu Zhi-An;Yao Shu-Hua;Zhou Jian;Xi Xiao-Xiang;Chen Y. B.;Chen Yan-Feng
电荷密度波(CDW)的形成归因于教科书中的费米面嵌套，但最近的研究揭示了电子-声子相互作用和缺陷的显著影响，对这一常见范式提出了挑战。过渡金属二卤化物是170K附近电荷密度波的原型，是探索CDW机理的理想平台。在这项工作中，我们通过对一系列()晶体的研究，揭示了缺陷对CDW的潜在影响。输运测量表明，在接近化学计量比的化合物附近，沿两个方向的电阻率-扭结特征(CDW指纹)在160K左右，而在轴向只有一个电阻率-扭结特征。值得注意的是，电阻扭结完全消失在。拉曼光谱不仅证实了相应的结构相变，而且通过对Γ相变前1相的理论费米面的分析，验证了布里渊区的电子-声子相互作用从原来的减弱。我们认为()沿轴向的CDW主要是由于电子-声子相互作用，而沿轴向的CDW是费米表面嵌套和电子-声子相互作用的协同作用；如果掺杂浓度足够高，CDW完全被掺杂引起的无序猝灭。我们的研究揭示了掺杂对CDW的微妙影响，并可能对掺杂Mott绝缘体中CDW与高温超导体的相互作用提供更多的线索。
The formation of charge density wave (CDW) is attributed to Fermi-surface nesting in textbooks, but this common paradigm is challenged by recent studies that reveal the pronounced effects of electron-phonon interaction and defects. Transition-metal dichalcogenide, being a prototype of charge density wave at around 170 K, is an ideal playground for exploring the mechanism of CDW. In this work, we reveal thesubtleeffect of defects on the CDW through studying a series of() crystals. Transport measurements show that, being close to the stoichiometric compound, have a resistivity-kink feature (fingerprint of CDW) around 160 K along both- andaxes;only has a resistivity-kink feature along theaxis. Remarkably, the resistivity kink completely disappears in. Raman spectroscopy not only confirms the corresponding structural phase transition, but also verifies decreased electron-phonon interaction at the Γ point of the Brillouin zone fromtobased on analysis of theoretical Fermi surface of 1phase ofbefore CDW phase transition. We propose that the CDW of() along theaxis is mainly due to electron-phonon interaction, while CDW along theaxis is the synergetic effect of Fermi-surface nesting and electron-phonon interaction; if dopant concentration is high enough, CDW is completely quenched by disorder induced by doping. Our study reveals the subtle effects of doping on CDW, and may give more hints on the interplay between CDW and high-temperature superconductor in the doped Mott insulators.