Optical transitions between entangled electron–phonon states in silicon

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F10974938%3A_____%2F25%3A25_88_26" target="_blank" >RIV/10974938:_____/25:25_88_26 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1063/5.0288893" target="_blank" >https://doi.org/10.1063/5.0288893</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/5.0288893" target="_blank" >10.1063/5.0288893</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Optical transitions between entangled electron–phonon states in silicon

Popis výsledku v původním jazyce

Silicon crystallizes in the diamond structure with two atoms per unit cell and supports three optical phonon modes. However, due to the centrosymmetric nature of the lattice, these modes do not induce a net dipole moment and are therefore inactive in infrared absorption. Even in polar semiconductors, where optical phonons can be IR-active, conventional techniques such as infrared absorption and Raman spectroscopy are restricted to probing phonons at the Brillouin zone center (Gamma-point). In this work, we demonstrate that time- and spectrally resolved pump-probe ellipsometry enables access to the coherent response of electron-phonon coupled states involving both valence and conduction bands. Following two-photon absorption induced by the femtosecond pump pulse, the electronic excitation relaxes and drives the generation of coherent longitudinal optical phonons along the X-direction of the Brillouin zone, followed by optical transitions of entangled electron-phonon states along the Lambda-direction. This process results in a transient, strongly correlated electron-phonon state that persists for up to approximate to 300 fs. Within this coherent time window, the silicon crystal exhibits optical resonances at electronic transition energies modulated by quantized phonon contributions. Finally, we detect further sidebands in the ellipsometric spectrum, which are 81 meV apart and assign these to two-phonon-assisted electronic transitions. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

Název v anglickém jazyce

Optical transitions between entangled electron–phonon states in silicon

Popis výsledku anglicky

Silicon crystallizes in the diamond structure with two atoms per unit cell and supports three optical phonon modes. However, due to the centrosymmetric nature of the lattice, these modes do not induce a net dipole moment and are therefore inactive in infrared absorption. Even in polar semiconductors, where optical phonons can be IR-active, conventional techniques such as infrared absorption and Raman spectroscopy are restricted to probing phonons at the Brillouin zone center (Gamma-point). In this work, we demonstrate that time- and spectrally resolved pump-probe ellipsometry enables access to the coherent response of electron-phonon coupled states involving both valence and conduction bands. Following two-photon absorption induced by the femtosecond pump pulse, the electronic excitation relaxes and drives the generation of coherent longitudinal optical phonons along the X-direction of the Brillouin zone, followed by optical transitions of entangled electron-phonon states along the Lambda-direction. This process results in a transient, strongly correlated electron-phonon state that persists for up to approximate to 300 fs. Within this coherent time window, the silicon crystal exhibits optical resonances at electronic transition energies modulated by quantized phonon contributions. Finally, we detect further sidebands in the ellipsometric spectrum, which are 81 meV apart and assign these to two-phonon-assisted electronic transitions. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

<a href="/cs/project/EF16_019%2F0000789" target="_blank" >EF16_019/0000789: Pokročilý výzkum s využitím fotonů a částic vytvořených vysoce intenzivními lasery</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Applied Physics Letters

ISSN

0003-6951

e-ISSN

1077-3118

Svazek periodika

127

Číslo periodika v rámci svazku

14

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

6

Strana od-do

141102 (1-6-)

Kód UT WoS článku

001590133000001

EID výsledku v databázi Scopus

2-s2.0-105018062721