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arXiv · 2312.15371

New three-dimensional dispersion in the type-II Dirac semimetals PtTe$_2$ and PdTe$_2$ revealed through Angle Resolved Photoemission Spectroscopy

Ivan Pelayo·Derek Bergner·Archibald J. Williams·Jiayuwen Qi·Penghao Zhu·Mahfuzun Nabi·Warren L. B. Huey·Luca Moreschini·Ziling Deng·Jonathan Denlinger·Alessandra Lanzara·Yuan-Ming Lu·Wolfgang Windl·Joshua Goldberger·Claudia Ojeda-Aristizabal
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Abstract

PtTe$_2$ and PdTe$_2$ are among the first transition metal dichalcogenides that were predicted to host type-II Dirac fermions, exotic particles prohibited in free space. These materials are layered and air-stable, which makes them top candidates for technological applications that take advantage of their anisotropic magnetotransport properties. Here, we provide a detailed characterization of the electronic structure of PtTe$_2$ and PdTe$_2$ using Angle Resolved Photoemission Spectroscopy (ARPES) and Density Functional Theory (DFT) calculations, unveiling a new three-dimensional dispersion in these materials. Through the use of circularly polarized light, we report a different behavior of such dispersion in PdTe$_2$ compared to PtTe$_2$, that we relate to a symmetry analysis of the dipole matrix element. Such analysis reveals a link between the observed circular dichroism and the different momentum-dependent terms in the dispersion of these two compounds, despite their close similarity in crystal structure. Additionally, our data shows a clear difference in the circular dichroic signal for the type-II Dirac cones characteristic of these materials, compared to their topologically protected surface states. Our work provides a useful reference for the ARPES characterization of other transition metal dichalcogenides with topological properties and illustrates the use of circular dichroism as a guide to identify the topological character of two otherwise equivalent band dispersions, and to recognize different attributes in the band structure of similar materials.

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Ivan Pelayo, Derek Bergner, Archibald J. Williams, Jiayuwen Qi, Penghao Zhu, Mahfuzun Nabi, Warren L. B. Huey, Luca Moreschini, Ziling Deng, Jonathan Denlinger, Alessandra Lanzara, Yuan-Ming Lu, Wolfgang Windl, Joshua Goldberger, Claudia Ojeda-Aristizabal. 2024-05-16. New three-dimensional dispersion in the type-II Dirac semimetals PtTe$_2$ and PdTe$_2$ revealed through Angle Resolved Photoemission Spectroscopy. https://arxiv.org/abs/2312.15371

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