In strongly correlated electron system, the impact of elementary substitution or intercalation plays a crucial role in determining electronic ground state among various macroscopic quantum phases such as charge order and superconductivity. Here, we report that simultaneous Cu intercalation and Ta substitution at Ti site in 1T-Cu x Ti0.8Ta0.2Se2 induce an intrinsic electronic phase diagram, characterized by an inherent superconducting transition in the x region of 0 ⩽ x ⩽ 0.12, with a maximum superconducting transition temperature T c of 2.5 K for x = 0.04, in contrast to the non-superconducting sample 1T-Cu0.04TiSe2. The increased density of free charge carriers screen the Coulomb interaction between electron-hole pairs effectively, promoting the occurrence of superconductivity favourably. Present results suggest that the Cu intercalation and the Ta substitution-induced suppression of the exciton condensation boost the superconductivity, shedding new light on the fundamental physics of the interplay between superconductivity, charge order, and electron correlation.

中文翻译：

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与抑制 1T-TiSe2 中激子形成相关的超导性


在强关联电子体系中，元素取代或插层的影响对于确定电荷序、超导等各种宏观量子相之间的电子基态起着至关重要的作用。在这里，我们报道了 1T-Cu x Ti0.8Ta0.2Se2 中 Ti 位点的同时 Cu 嵌入和 Ta 取代诱导了本征电子相图，其特征是 0 ⩽ x ⩽ 0.12 的 x 区域中固有的超导转变，具有当 x = 0.04 时，最大超导转变温度 T c 为 2.5 K，与非超导样品 1T-Cu0.04TiSe2 相比。自由载流子密度的增加有效地屏蔽了电子-空穴对之间的库仑相互作用，有利于促进超导的发生。目前的结果表明，Cu 嵌入和 Ta 取代引起的激子凝聚抑制增强了超导性，为超导性、电荷有序性和电子相关性之间相互作用的基础物理提供了新的线索。