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A fundamental understanding of hot-carrier dynamics in photo-excited metal nanostructures is needed to unlock their potential for photodetection and photocatalysis. Despite numerous studies on the ultrafast dynamics of hot electrons, so far, the temporal evolution of hot holes in metal-semiconductor heterostructures remains unknown. Here, we report ultrafast (t < 200 fs) hot-hole injection from Au nanoparticles into the valence band of p-type GaN. The removal of hot holes from below the Au Fermi level is observed to substantially alter the thermalization dynamics of hot electrons, reducing the peak electronic temperature and the electron-phonon coupling time of the Au nanoparticles. First-principles calculations reveal that hot-hole injection modifies the relaxation dynamics of hot electrons in Au nanoparticles by modulating the electronic structure of the metal on timescales commensurate with electron-electron scattering. These results advance our understanding of hot-hole dynamics in metal-semiconductor heterostructures and offer additional strategies for manipulating the dynamics of hot carriers on ultrafast timescales. Photo-excited gold nanoparticles are shown to provide ultrafast and efficient hot-hole injection to the valence band of p-type GaN, substantially altering hot-electron dynamics in the nanoparticles and forming a basis to design hot-hole-based optoelectronics.

Designing new quantum materials with long-lived electron spin states urgently requires a general theoretical formalism and computational technique to reliably predict intrinsic spin relaxation times. We present a new, accurate and universal first-principles methodology based on Lindbladian dynamics of density matrices to calculate spin-phonon relaxation time of solids with arbitrary spin mixing and crystal symmetry. This method describes contributions of Elliott-Yafet and D'yakonov-Perel' mechanisms to spin relaxation for systems with and without inversion symmetry on an equal footing. We show that intrinsic spin and momentum relaxation times both decrease with increasing temperature; however, for the D'yakonov-Perel' mechanism, spin relaxation time varies inversely with extrinsic scattering time. We predict large anisotropy of spin lifetime in transition metal dichalcogenides. The excellent agreement with experiments for a broad range of materials underscores the predictive capability of our method for properties critical to quantum information science.

Designing new quantum materials with long-lived electron spin states urgently requires a general theoretical formalism and computational technique to reliably predict intrinsic spin relaxation times. We present a new, accurate and universal first-principles methodology based on Lindbladian dynamics of density matrices to calculate spin-phonon relaxation time of solids with arbitrary spin mixing and crystal symmetry. This method describes contributions of Elliott-Yafet and D'yakonov-Perel' mechanisms to spin relaxation for systems with and without inversion symmetry on an equal footing. We show that intrinsic spin and momentum relaxation times both decrease with increasing temperature; however, for the D'yakonov-Perel' mechanism, spin relaxation time varies inversely with extrinsic scattering time. We predict large anisotropy of spin lifetime in transition metal dichalcogenides. The excellent agreement with experiments for a broad range of materials underscores the predictive capability of our method for properties critical to quantum information science.

A fundamental understanding of hot-carrier dynamics in photo-excited metal nanostructures is needed to unlock their potential for photodetection and photocatalysis. Despite numerous studies on the ultrafast dynamics of hot electrons, so far, the temporal evolution of hot holes in metal-semiconductor heterostructures remains unknown. Here, we report ultrafast (t < 200 fs) hot-hole injection from Au nanoparticles into the valence band of p-type GaN. The removal of hot holes from below the Au Fermi level is observed to substantially alter the thermalization dynamics of hot electrons, reducing the peak electronic temperature and the electron-phonon coupling time of the Au nanoparticles. First-principles calculations reveal that hot-hole injection modifies the relaxation dynamics of hot electrons in Au nanoparticles by modulating the electronic structure of the metal on timescales commensurate with electron-electron scattering. These results advance our understanding of hot-hole dynamics in metal-semiconductor heterostructures and offer additional strategies for manipulating the dynamics of hot carriers on ultrafast timescales.

Antecedentes: La nueva generación de anticoagulantes, llamados también anticoagulantes orales directos (DOACs), tienen características que los vuelven más predecibles por su acción farmacocinética y farmacodinamia, rango terapéutico y dosis fijas sin necesidad de monitorización periódica. En la actualidad se conocen 2 tipos: inhibidores directos del FX activado (FXa) e inhibidores de la trombina (FIIa). Objetivo: Evaluar la indicación de suspensión de los anticoagulantes orales directos en pacientes sometidos a procedimientos de cirugía oral basado en la evidencia científica. Materiales y métodos: En esta revisión sistemática de la literatura se efectuaron búsquedas en las bases de datos de PubMed, Embase-Elsevier, EBSCO, Scopus, Science direct, Cochrane, Scielo, Ovid y ProQuest de artículos publicados entre el 1 de enero de 2010 al 31 de marzo de 2021. Se obtuvieron y analizaron 17 artículos que cumplían con los criterios de inclusión y exclusión. Resultados: En los 17 artículos, fueron evaluados un total de 840 pacientes anticoagulados con rivaroxaban, apixaban, dabigatrán y edoxaban, en los cuales se realizaron procedimientos de cirugía oral, sobre todo exodoncias e implantes dentales; dentro de estos a 782 pacientes no se les retiró el DOAC previo al procedimiento de cirugía oral y a 58 pacientes se les omitió al menos una dosis del anticoagulante. Se presentó hemorragias, principalmente leves en 17,51% de los pacientes a los que no se les retiro el DOAC. Se encontró un mayor porcentaje de hemorragias asociadas a rivaroxaban que con los demás DOACs. Conclusiones: Se recomienda no suspender los DOACs en procedimientos de cirugía oral menor, ya que la hemorragia que pudiera presentarse es generalmente leve y puede ser adecuadamente manejada con medidas hemostáticas locales.