SKM 2023 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 57: Poster: Superconductivity I

TT 57.8: Poster

Donnerstag, 30. März 2023, 15:00–18:00, P2/OG2

High pressure T-P phase diagram of 2H-TaSe₂ — •Yuliia Tymoshenko¹, Xingchen Shen¹, Amir-Abbas Haghighirad¹, Tom Lacmann¹, Gaston Garbarino², and Frank Weber¹ — ¹Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany — ²European Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, Grenoble 38043, France

Many layered materials featuring charge-density waves (CDW), a modulation of the electronic density of states, acquire a superconducting ground state often associated with a quantum critical point (QCP) of the CDW order. Although 2H polymorph of tantalum diselenide (2H-TaSe₂) with a layered hexagonal crystal structure is one of the most studied CDW systems, to the best of our knowlege, previous studies of the phase diagram have not been carried out at pressures sufficient to suppress the CDW order at low temperatures. We investigated the CDW phase diagram in its most crucial but still unexplored area and determined the CDW quantum critical point in 2H-TaSe₂ under pressure via high-resolution synchrotron x-ray diffraction (XRD). Its position together with previously published resistivity measurements and our recent ambient-pressure study of the soft phonon mode at the CDW transition enable us to argue that this compound likely has a CDW quantum critical point closely connected to the emergent superconducting phase. This can serve as a textbook example where both phases are mediated by the same mechanism, electron-phonon coupling of the CDW soft phonon mode.