Publications and Preprints

CSULB student co-authors are in bold and asterisk (*) denotes publications have co-authorship from both CSULB and OSU PREM partners.

Observation of a new three-dimensional Dirac-like dispersion in the type-II Dirac semimetals PtTe2 and PdTe2*

(preprint) Ivan Pelayo, Derek Bergner, Archibald J. Williams, Jiayuwen Qi, Mahfuzun Nabi, Warren L. B. Huey, Luca Moreschini, Ziling Deng, Jonathan Denlinger, Alessandra Lanzara, Wolfgang Windl, Joshua Goldberger, Claudia Ojeda-Aristizabal. "Observation of a new three-dimensional Dirac-like dispersion in the type-II Dirac semimetals PtTe2 and PdTe2", arXiv 2312.15371 (2023) https://arxiv.org/abs/2312.15371

PtTe2 and PdTe2 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. The PREM team was able to experimentally characterize the electronic band structure of PtTe2 and PdTe2 using Angle Resolved Photoemission Spectroscopy ARPES and Density Functional Theory DFT calculations, unveiling a new three-dimensional Dirac-like dispersion in these materials.

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Electronic transport mechanisms in a thin crystal of the Kitaev candidate α-RuCl3 probed through guarded high impedance measurements

Patrick Barfield, Vinh Tran, Vikram Nagarajan, Maya Martinez, Amirari Diego, Derek Bergner, Alessandra Lanzara, James G. Analytis and Claudia Ojeda-Aristizabal. "Electronic transport mechanisms in a thin crystal of the Kitaev candidate α-RuCl3 probed through guarded high impedance measurements", Appl. Phys. Lett. 122, 243102 (2023) https://pubs.aip.org/aip/apl/article-abstract/122/24/243102/2896115/Ele…

α-RuCl3 is considered to be the top candidate material for the experimental realization of the celebrated Kitaev model, where ground states are quantum spin liquids with interesting fractionalized excitations. It is, however, known that additional interactions beyond the Kitaev model trigger in α-RuCl3 a long-range zigzag antiferromagnetic ground state. In this work, we investigate a nanoflake of α-RuCl3 through guarded high impedance measurements aimed at reaching the regime where the system turns into a zigzag antiferromagnet. We found that below about 30 Kelvin, transport is ruled by Efros–Shklovskii variable range hopping (VRH). Most importantly, our data show that below the magnetic ordering transition known for bulk α-RuCl3 in the frame of the Kitaev–Heisenberg model (⁠7 Kelvin), there is a clear deviation from VRH or thermal activation transport mechanisms. Our work demonstrates the possibility of reaching, through specialized high impedance measurements, the thrilling ground states predicted for α-RuCl3 at low temperatures in the frame of the Kitaev–Heisenberg model and informs about the transport mechanisms in this material in a wide temperature range.

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