scholarly journals Polaron Trapping and Migration in Iron-Doped Lithium Niobate

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 302
Author(s):  
Laura Vittadello ◽  
Laurent Guilbert ◽  
Stanislav Fedorenko ◽  
Marco Bazzan
Keyword(s):  
Lithium Niobate ◽  
Laser Pulse ◽  
Charge Transport ◽  
Small Polaron ◽  
Deep Trap ◽  
Polaron Hopping ◽  
And Migration ◽  
Kinetics Of ◽  
Photoinduced Charge ◽  
Absorption Measurements

Photoinduced charge transport in lithium niobate for standard illumination, composition and temperature conditions occurs by means of small polaron hopping either on regular or defective lattice sites. Starting from Marcus-Holstein’s theory for polaron hopping frequency we draw a quantitative picture illustrating two underlying microscopic mechanisms besides experimental observations, namely direct trapping and migration-accelerated polaron trapping transport. Our observations will be referred to the typical outcomes of transient light induced absorption measurements, where the kinetics of a polaron population generated by a laser pulse then decaying towards deep trap sites is measured. Our results help to rationalize the observations beyond simple phenomenological models and may serve as a guide to design the material according to the desired specifications.

scholarly journals Small-Polaron Hopping and Low-Temperature (45–225 K) Photo-Induced Transient Absorption in Magnesium-Doped Lithium Niobate

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 809
Author(s):  
Simon Messerschmidt ◽  
Andreas Krampf ◽  
Laura Vittadello ◽  
Mirco Imlau ◽  
Tobias Nörenberg ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Temperature Regime ◽  
Transient Absorption ◽  
Small Polaron ◽  
Good Representation ◽  
Temperature Dependent ◽  
Polaron Hopping ◽  
Two Parameters ◽  
Oppositely Charged ◽  
Small Polarons

A strongly temperature-dependent photo-induced transient absorption is measured in 6.5 mol% magnesium-doped lithium niobate at temperatures ranging from 45 K to 225 K. This phenomenon is interpreted as resulting from the generation and subsequent recombination of oppositely charged small polarons. Initial two-photon absorptions generate separated oppositely charged small polarons. The existence of these small polarons is monitored by the presence of their characteristic absorption. The strongly temperature-dependent decay of this absorption occurs as series of thermally assisted hops of small polarons that facilitate their merger and ultimate recombination. Our measurements span the high-temperature regime, where small-polaron jump rates are Arrhenius and strongly dependent on temperature, and the intermediate-temperature regime, where small-polaron jump rates are non-Arrhenius and weakly dependent on temperature. Distinctively, this model provides a good representation of our data with reasonable values of its two parameters: Arrhenius small-polaron hopping’s activation energy and the material’s characteristic phonon frequency.

Charge Transport Mechanism in Molecularly Doped Polymers

1992 ◽  
Vol 277 ◽  
Author(s):  
H. Nishizawa ◽  
M. Sugiuchi ◽  
T. Uehara
Keyword(s):  
Charge Transport ◽  
Coulomb Interaction ◽  
Transport Mechanism ◽  
Small Polaron ◽  
Dipole Interaction ◽  
Charge Transport Mechanism ◽  
Polaron Hopping ◽  
Small Polaron Hopping ◽  
Mobility Behavior ◽  
Doped Polymers

Charge-dipole interaction effects in molecularly doped polymers are discussed. The charge-dipole Coulomb interaction makes exponentially distributed traps. Calculating the mobility with their traps leads to mobility behavior like Gill's equation. The cancellation of a dipole corresponds to coincidence events of small-polaron hopping.

scholarly journals Electronic Charge Transport: Breakdown of the Small‐Polaron Hopping Model in Higher‐Order Spinels (Adv. Mater. 49/2020)

2020 ◽  
Vol 32 (49) ◽  
pp. 2070368
Author(s):  
Anuj Bhargava ◽  
Roni Eppstein ◽  
Jiaxin Sun ◽  
Michelle A. Smeaton ◽  
Hanjong Paik ◽  
...  
Keyword(s):  
Charge Transport ◽  
Small Polaron ◽  
Higher Order ◽  
Electronic Charge ◽  
Polaron Hopping ◽  
Small Polaron Hopping ◽  
Hopping Model

scholarly journals Small Polaron Hopping in Fe:LiNbO3 as a Function of Temperature and Composition

Crystals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 294 ◽  
Author(s):  
Laura Vittadello ◽  
Marco Bazzan ◽  
Simon Messerschmidt ◽  
Mirco Imlau
Keyword(s):  
Charge Transport ◽  
Transient Absorption ◽  
Small Polaron ◽  
Transient Absorption Spectroscopy ◽  
Relaxation Dynamics ◽  
Experimental Conditions ◽  
Polaron Hopping ◽  
Small Polaron Hopping ◽  
Wide Range ◽  
Temperature Ranges

Small-polaron hopping involved in charge transport in Fe-doped congruent lithium niobate is investigated as a function of temperature and composition by means of light-induced transient absorption spectroscopy. The relaxation dynamics of the light-induced polaron population is characterized by individual activation energies within different temperature ranges. A numerical investigation carried out by Monte Carlo simulations reveals that these findings may be understood in terms of the varying abundance of the different types of hops that the polarons may perform among regular or defective lattice sites. The role of the temperature and of the sample composition on the distribution of the different hop types is thus explored for a wide range of parameters, allowing one to preview the charge transport properties for a given set of experimental conditions.

Vertical Charge Transport via Small Polaron Hopping within TIPS-Pentacene Lamellar Single Crystal

Small ◽  
2017 ◽  
Vol 13 (25) ◽  
pp. 1700456 ◽  
Author(s):  
Jiawei Wang ◽  
Tianjun Liu ◽  
Ji Dong ◽  
Molin Li ◽  
Jun He ◽  
...  
Keyword(s):  
Single Crystal ◽  
Charge Transport ◽  
Small Polaron ◽  
Polaron Hopping ◽  
Small Polaron Hopping
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