6533b7dbfe1ef96bd1271664
RESEARCH PRODUCT
Thickness-dependent electron momentum relaxation times in iron films
Jacek ArabskiMischa BonnGuy SchmerberDmitry TurchinovichKeno L. KrewerKeno L. KrewerWentao ZhangEric Beaurepairesubject
Materials sciencePhysics and Astronomy (miscellaneous)FOS: Physical sciences02 engineering and technologyElectronConductivity01 natural sciencesElectric field0103 physical sciencesMesoscale and Nanoscale Physics (cond-mat.mes-hall)Scaling010302 applied physicsMomentum (technical analysis)Condensed Matter - Materials ScienceCondensed matter physics[PHYS.PHYS]Physics [physics]/Physics [physics]Condensed Matter - Mesoscale and Nanoscale PhysicsRelaxation (NMR)Materials Science (cond-mat.mtrl-sci)Physik (inkl. Astronomie)021001 nanoscience & nanotechnologyThermal conductionCondensed Matter - Other Condensed MatterFemtosecond0210 nano-technologyOther Condensed Matter (cond-mat.other)description
Terahertz time-domain conductivity measurements in 2 to 100 nm thick iron films resolve the femtosecond time delay between applied electric fields and resulting currents. This current response time decreases from 29 fs for thickest films to 7 fs for the thinnest films. The macroscopic response time is not strictly proportional to the conductivity. This excludes the existence of a single relaxation time universal for all conduction electrons. We must assume a distribution of microscopic momentum relaxation times. The macroscopic response time depends on average and variation of this distribution; the observed deviation between response time and conductivity scaling corresponds to the scaling of the variation. The variation of microscopic relaxation times depends on film thickness because electrons with different relaxation times are affected differently by the confinement since they have different mean free paths.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2020-01-01 |