Photoinduced electronic band dynamics and defect-mediated surface potential evolution in PdSe2.

Λεπτομέρειες βιβλιογραφικής εγγραφής
Τίτλος:	Photoinduced electronic band dynamics and defect-mediated surface potential evolution in PdSe2.
Συγγραφείς:	Abdul-Aziz, Omar, Tuniz, Manuel, Bronsch, Wibke, Parmigiani, Fulvio, Cilento, Federico, Wolverson, Daniel, Sayers, Charles J., Cerullo, Giulio, Dallera, Claudia, Carpene, Ettore, van Loosdrecht, Paul H. M., Hedayat, Hamoon
Πηγή:	NPJ 2D Materials & Applications; 12/12/2025, Vol. 9 Issue 1, p1-8, 8p
Θεματικοί όροι:	Surface potential, Surface photovoltage, Photons, Nanostructured materials, Semiconductors, Picosecond pulses, Photoelectron spectroscopy
Περίληψη:	We use time- and angle-resolved photoemission spectroscopy (TR-ARPES) combined with density functional theory to investigate ultrafast carrier dynamics in low-symmetry layered semiconducting PdSe2. The indirect bandgap is determined to be 0.55 eV. Following photoexcitation above this gap, we resolve a valence band shift and broadening, both lasting less than a picosecond, consistent with bandgap renormalization and carrier scattering, indicative of strong many-body interactions. Subsequently, hot carriers populate the conduction band minimum and are captured by defect states. A surface photovoltage (SPV) of ~67 meV emerges, persisting for over 50 ps, driven by defect-assisted charge separation. The formation of native vacancies, promoted by the low-symmetry lattice, likely gives rise to the mid-gap states responsible for this long-lived SPV response. Detailed analysis of TR-ARPES spectra disentangles the contributions of bandgap renormalization, carrier scattering, defect states, and SPV. These findings establish PdSe2 as a prototypical layered quantum material exhibiting exotic photoresponses on ultrafast timescales. [ABSTRACT FROM AUTHOR]
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Βάση Δεδομένων:	Complementary Index

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