Emergence of charge density wave domain walls above the superconducting dome in 1T-TiSe2

By Young Il Joe, X. M. Chen, Pouyan Ghaemi, K. Finkelstein, G. D. L. Peña, Y. Gan, J. C. Lee, S. Yuan, J. Geck, G. MacDougall and 4 more. Nature Physics, 2013

270 citations recorded by the source corpus.

When the charge density wave state in TiSe2 is suppressed by hydrostatic pressure or chemical doping, superconductivity appears. This suggests the presence of a quantum critical point. Yet a high pressure X-ray study unexpectedly finds that the quantum critical point is nowhere near the superconducting dome. Superconductivity in so-called unconventional superconductors is nearly always found in the vicinity of another ordered state, such as antiferromagnetism, charge density wave (CDW), or stripe order. This suggests a fundamental connection between superconductivity and fluctuations in some other order parameter. To better understand this connection, we used high-pressure X-ray scattering to directly study the CDW order in the layered dichalcogenide TiSe2, which was previously shown to exhibit superconductivity when the CDW is suppressed by pressure1 or intercalation of Cu atoms2. We succeeded in suppressing the CDW fully to zero temperature, establishing for the first time the existence of a quantum critical point (QCP) at Pc = 5.1 ± 0.2 GPa, which is more than 1 GPa beyond the end of the superconducting region. Unexpectedly, at P = 3 GPa we observed a reentrant, weakly first order, incommensurate phase, indicating the presence of a Lifshitz tricritical point somewhere above the superconducting dome. Our study suggests that superconductivity in TiSe2 may not be connected to the QCP itself, but to the formation of CDW domain walls.

Subfields: Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/738bb16a6a82048a34de564699e3d612a9b67251

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In Electronic, Optical and Magnetic Materials

1. Yang Ding
2. Lin Wang
3. Bing Li
4. H. Mao
5. Xiao-Jia Chen

In Materials Chemistry

1. Yang Ding
2. Lin Wang
3. Bing Li
4. H. Mao
5. Xiao-Jia Chen

Citations in the corpus

• Solids, liquids, and gases under high pressure (2018, background): “A high-P x-ray scattering study (Joe et al., 2014) directly detected the emergence of the CDW domain walls above the superconducting dome in 1T-TiSe2.”