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arXiv · 1710.04096

Energy-dependent spatial texturing of the charge order in $1T$-Cu$_x$TiSe$_2$

Marcello Spera·Alessandro Scarfato·Enrico Giannini·Christoph Renner
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Abstract

We report a detailed study of the microscopic effects of Cu intercalation on the charge density wave (CDW) in 1\textit{T}-Cu$_x$TiSe$_2$. Scanning tunneling microscopy and spectroscopy (STM/STS) reveal a unique, Cu driven spatial texturing of the charge ordered phase, with the appearance of energy dependent CDW patches and sharp $π$-phase shift domain walls ($π$DWs). The energy and doping dependencies of the patchwork are directly linked to the inhomogeneous potential landscape due to the Cu intercalants. They imply a CDW gap with unusual features, including a large amplitude, the opening below the Fermi level and a shift to higher binding energy with electron doping. Unlike the patchwork, the $π$DWs occur independently of the intercalated Cu distribution. They remain atomically sharp throughout the investigated phase diagram and occur both in superconducting and non-superconducting specimen. These results provide unique atomic-scale insight on the CDW ground state, questioning the existence of incommensurate CDW domain walls and contributing to understand its formation mechanism and interplay with superconductivity.

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Marcello Spera, Alessandro Scarfato, Enrico Giannini, Christoph Renner. 2018-12-14. Energy-dependent spatial texturing of the charge order in $1T$-Cu$_x$TiSe$_2$. https://doi.org/10.1103/physrevb.99.155133

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