Thickness-Dependent Spintronic Terahertz Emission in Molecular Beam Epitaxy-Grown PtTe2: From Semiconductor to Type-II Dirac Semimetal
Abstract Spintronic THz emitters are the most practical broadband sources, but their performance is constrained by the spin Hall conductivity of the conversion layer. We show that PtTe2, a type II Dirac semimetal, overcomes this limitation through thickness-driven electronic phase control. Growing PtTe2 films from 1 to 20 monolayers (MLs) by molecular beam epitaxy, we find that THz emission mirrors the electronic phase diagram: it remains weak in the semiconducting single layer, turns on sharply at the semimetal transition near 2 ML, and reaches a maximum at 10 ML. When compared to a reference Pt emitter, this thickness dependence cannot be explained by an intrinsic inverse spin Hall effect but points to a spin-to-charge conversion dominated by the inverse Rashba-Edelstein effect involving topological surface states and Rashba spin splitting. First-principles calculations reproduce this picture quantitatively. These results establish the thickness engineering of van der Waals semimetals as a practical strategy for optimizing spintronic THz emitters and devices.
Authors
- Armando Pezo (ORCID: https://orcid.org/0000-0003-2613-3808)
- A. Marty (ORCID: https://orcid.org/0000-0001-5709-6945)
- Matthieu Jamet (ORCID: https://orcid.org/0000-0002-8247-4677)
- Fatima Ibrahim (ORCID: https://orcid.org/0000-0002-7374-6001)
- Isabelle Gomes de Moraes (ORCID: https://orcid.org/0000-0001-8702-722X)
- Rahul Sharma (ORCID: https://orcid.org/0000-0002-5945-5371)
- Ravi K. Biroju (ORCID: https://orcid.org/0000-0002-4152-7509)
- S. Massabeau (ORCID: https://orcid.org/0009-0009-1769-4620)
- Henri Jaffres (ORCID: https://orcid.org/0000-0002-2730-1255)
- Ekta Yadav (ORCID: https://orcid.org/0000-0001-7687-9339)
- Mairbek Chshiev (ORCID: https://orcid.org/0000-0001-9232-7622)
- Viliam Vretenár (ORCID: https://orcid.org/0000-0002-2730-2872)
- Jean‐Marie George (ORCID: https://orcid.org/0000-0001-7422-0418)
- Jing Li (ORCID: https://orcid.org/0000-0002-9283-3821)
- Adrien Michon (ORCID: https://orcid.org/0000-0002-8870-3696)
- Sukhdeep Dhillon
Institutions
- Slovak University of Technology in Bratislava (SK)
- Centre National de la Recherche Scientifique (FR)
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR)
- Université Paris-Saclay (FR)
- CEA Grenoble (FR)
- Sorbonne Université (FR)
- Direction de la Recherche Technologique (FR)
- Spintronique et Technologie des Composants (FR)
- Laboratoire d'Électronique des Technologies de l'Information (FR)
- Université Paris 1 Panthéon-Sorbonne (FR)
- Vellore Institute of Technology University (IN)
- Université Grenoble Alpes (FR)
Publication Details
- Journal
- Nano Letters
- Published
- 2026-10-06
- DOI
- https://doi.org/10.1021/acs.nanolett.6c02467
- Primary Topic
- Magnetic properties of thin films
- Type
- article
- Field-Weighted Citation Impact
- 0.00