Transition metal chalcogenides under extreme pressure

The aim of this research project is to study the high-pressure phase diagram of transition metal chalcogenides. Combining several fully ab initio and state-of-the-art methods, we are searching for new high-pressure structures, determine electronic and vibrational properties of stable structures, as well as calculate their electron-phonon coupling (EPC), superconducting properties, and instabilities towards charge-density wave (CDW) ordering.

By doing so, this project contributes to obtain a more complete picture of the high-pressure phase diagram of TMCs, providing a solid foundation for future high-pressure research. In addition, the results of this project help to (i) clarify the effects of high-pressure on atomic bonding, (ii) improve the understanding of the mechanisms behind SC and charge order under pressure, and (iii) shed light on the interactions between coexisting SC and CDW order in these materials.

This project is supported by the Austrian Science Fund (FWF).

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Superconducting hydrides under high pressure

Due to its low atomic mass leading to high energy vibrational modes, hydrogen has been under consideration for conventional high-Tc superconductivity since 1968 (Ashcroft, PRL 21, 1748). Metallicity is a prerequisite for superconductivity and while it has not yet been possible to get pure hydrogen in a metallic state experimentally, Drozdov, (Nature volume 525, pages 73–76) reported superconductivity above 200 K in sulfur-hydride at approx. 200 GPa pressure. Since then the research field of superconducting hydrides has expanded greatly and several new, fascinating highest-Tc superconductors have been investigated in the hunt for room temperature superconductivity at ambient pressures.

This research project is performed in close collaboration with the groups of Prof. Lilia Boeri at the Sapienza University of Rome and of Prof. Elena Roxana Margine at the Binghamton University, SUNY, USA.

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Superconductivity in organic nanomaterials

In this externally funded research project we are investigating the electron-phonon mediated superconductivity in carbon-based, low- dimensional systems, such as nanosheets and nanoribbons, and using ab initio calculations and machine learn- ing, we design and predict new superconducting structures and materials.

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Latest Publications

Probing magnetic exchange interactions with helium
C. Trainer, C.M. Yim, C. Heil, L.S. Farrar, V. Tsurkan, A. Loidl, and P. Wahl
Phys. Rev. Lett. 127, 166803

LaBH8: the first high-Tc low-pressure superhydride
S. di Cataldo, C. Heil, W. von der Linden, and L. Boeri
Phys. Rev. B 104, L020511 (2021), doi:10.1103/PhysRevB.104.L020511

Strain-Stabilized (π,π) Order at the Surface of Fe1+xTe
C.M. Yim, S.N. Panja, C. Trainer, C. Topping, C. Heil, A.S. Gibbs, O.V. Magdysyuk, V. Tsurkan, A. Loidl, A.W. Rost, and P. Wahl
Nano Lett., doi: 10.1021/acs.nanolett.0c04821

Superconductivity and strong anharmonicity in novel Nb-S phases
R. Lucrezi and C. Heil
J. Phys.: Condens. Matter 33, 174001 (2021), doi: 10.1088/1361-648X/abda7a

Magnetic surface reconstruction in the van-der-Waals antiferromagnet Fe_{1+x}Te
C. Trainer, M. Songvilay, N. Qureshi, A. Stunault, C. M. Yim, E. E. Rodriguez, C. Heil, V. Tsurkan, A. Loidl, P. Wahl, and C. Stock
Phys. Rev. B 103, 024406 (2021), doi:10.1103/PhysRevB.103.024406

Electronic, vibrational, and electron-phonon coupling properties in SnSe2 and SnS2 under pressure
G. P. Kafle, C. Heil, H. Paudyal, and E. R. Margine
J. Mater. Chem. C 8 (46), 16404, 2020, doi: 10.1039/D0TC04356G