Unconventional superconducting phase diagram of monolayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>WTe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
The existence of a quantum critical point (QCP) and fluctuations around it are believed to be important for understanding the phase diagram in unconventional superconductors such as cuprates, iron pnictides, and heavy fermion superconductors. However, the QCP is usually buried deep within the superconducting dome and is difficult to investigate. The connection between quantum critical fluctuations and superconductivity remains an outstanding problem in condensed matter. Here combining both electrical transport and Nernst experiments, we explicitly demonstrate the onset of superconductivity at an unconventional QCP in gate-tuned monolayer tungsten ditelluride <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mo>(</a:mo><a:msub><a:mi>WTe</a:mi><a:mn>2</a:mn></a:msub><a:mo>)</a:mo></a:mrow></a:math>, with features incompatible with the conventional Bardeen-Cooper-Schrieffer scenario. The results lead to a superconducting phase diagram that is distinguished from other known superconductors. Two distinct gate-tuned quantum phase transitions are observed at the ends of the superconducting dome. We find that quantum fluctuations around the QCP of the underdoped regime are essential for understanding how the monolayer superconductivity is established. The unconventional phase diagram we report here illustrates a previously unknown relation between superconductivity and QCP.
Authors
- Yue Tang (ORCID: https://orcid.org/0000-0003-0506-5455)
- Ayelet J. Uzan
- Zhaoyi Joy Zheng (ORCID: https://orcid.org/0000-0001-7016-4447)
- Leslie Mareike Schoop (ORCID: https://orcid.org/0000-0003-3459-4241)
- Ratnadwip Singha (ORCID: https://orcid.org/0000-0002-3155-2137)
- Tiancheng Song (ORCID: https://orcid.org/0000-0002-6845-6624)
- R. J. Cava (ORCID: https://orcid.org/0000-0002-3294-6867)
- Sanfeng Wu
- Takashi Taniguchi (ORCID: https://orcid.org/0000-0002-1467-3105)
- Xin Gui (ORCID: https://orcid.org/0000-0003-0616-2150)
- Kenji Watanabe (ORCID: https://orcid.org/0000-0003-3701-8119)
- N. P. Ong (ORCID: https://orcid.org/0000-0001-7166-1058)
- Michael Onyszczak (ORCID: https://orcid.org/0000-0001-9411-2369)
- Haosen Guan (ORCID: https://orcid.org/0000-0001-5100-0092)
- Yanyu Jia (ORCID: https://orcid.org/0000-0001-6061-8441)
- Yu Guo (ORCID: https://orcid.org/0000-0003-1458-7220)
Institutions
- University of Wisconsin–Madison (US)
- University of Pittsburgh (US)
- Princeton University (US)
- National Institute for Materials Science (JP)
Publication Details
- Journal
- Physical Review Research
- Published
- 2025-02-28
- DOI
- https://doi.org/10.1103/physrevresearch.7.013224
- Citations
- 2
- Primary Topic
- Iron-based superconductors research
- Type
- article
- Field-Weighted Citation Impact
- 0.85
Funders
- National Science Foundation
- David and Lucile Packard Foundation
- U.S. Department of Energy
- Gordon and Betty Moore Foundation
- Wisconsin Alumni Research Foundation
- University of Wisconsin-Madison
- Ministry of Education, Culture, Sports, Science and Technology
- Materials Research Science and Engineering Center, Harvard University
- Japan Society for the Promotion of Science
- Office of Naval Research
- Air Force Office of Scientific Research