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The fast decay of carrier inversion in photoexcited graphene has been attributed to optical phonon emission and Auger recombination. Plasmon emission provides another pathway that, as we show here, drives the carrier relaxation dynamics on…

Mesoscale and Nanoscale Physics · Physics 2016-01-20 J. M. Hamm , A. F. Page , J. Bravo-Abad , F. J. Garcia-Vidal , O. Hess

Broken symmetries in graphene affect the massless nature of its charge carriers. We present an analysis of scattering by defects in graphene in the presence of spin-orbit interactions (SOIs). A characteristic constant ratio ($\simeq 2$) of…

Mesoscale and Nanoscale Physics · Physics 2014-04-10 Mahmoud M. Asmar , Sergio E. Ulloa

We have measured the ultrafast anisotropic optical response of highly doped graphene to an intense single cycle terahertz pulse. The time profile of the terahertz-induced anisotropy signal at 800 nm has minima and maxima repeating those of…

Mesoscale and Nanoscale Physics · Physics 2019-05-23 A. A. Melnikov , A. A. Sokolik , A. V. Frolov , S. V. Chekalin , E. A. Ryabov

Using ultrafast optical pump-probe spectroscopy, we have measured carrier relaxation times in epitaxial graphene layers grown on SiC wafers. We find two distinct time scales associated with the relaxation of nonequilibrium photogenerated…

Materials Science · Physics 2019-06-05 Jahan M. Dawlaty , Shriram Shivaraman , Mvs Chandrashekhar , Farhan Rana , Michael G. Spencer

We present a joint theory-experiment study on ultrafast photoluminescence from photoexcited graphene. Based on a microscopic theory, we reveal two distinct mechanisms behind the occurring photoluminescence: Besides the well-known incoherent…

Mesoscale and Nanoscale Physics · Physics 2015-07-28 Torben Winzer , Richard Ciesielski , Matthias Handloser , Alberto Comin , Achim Hartschuh , Ermin Malic

We demonstrated theoretically that the renormalization of the electron energy spectrum near the Dirac point of graphene by a strong high-frequency electromagnetic field (dressing field) drastically depends on polarization of the field.…

Mesoscale and Nanoscale Physics · Physics 2016-02-04 K. Kristinsson , O. V. Kibis , S. Morina , I. A. Shelykh

While the Dirac band structure of graphene has established it as a leading platform for ultrafast optoelectronics, its non-perturbative nonlinear response under intense excitation remains poorly understood. Here, we report ultrafast…

Optics · Physics 2026-04-27 Xiaolong Lv , Yu Zhang , Yuxuan Wei , Chuanshan Tian

We determine the spin-lifetime anisotropy of spin-polarized carriers in graphene. In contrast to prior approaches, our method does not require large out-of-plane magnetic fields and thus it is reliable for both low- and high-carrier…

We examine the photoconductivity of an intrinsic graphene associated with far- and mid-infrared irradiation at low temperatures. The model under consideration accounts for the excitation of the electron-hole pairs by incident radiation, the…

Materials Science · Physics 2008-05-27 F. T. Vasko V. Ryzhii

Since graphene has no band gap, photoluminescence is not expected from relaxed charge carriers. We have, however, observed significant light emission from graphene under excitation by ultrashort (30-fs) laser pulses. Light emission was…

Mesoscale and Nanoscale Physics · Physics 2010-09-20 Chun Hung Lui , Kin Fai Mak , Jie Shan , Tony F. Heinz

Saturable absorption is a non-perturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus…

Mesoscale and Nanoscale Physics · Physics 2017-03-15 A. Marini , J. D. Cox , F. J. Garcia de Abajo

In this work, high field carrier transport in two dimensional (2D) graphene is investigated. Analytical models are applied to estimate the saturation currents in graphene, based on the high scattering rate of optical phonon emission.…

Materials Science · Physics 2011-09-13 Tian Fang , Aniruddha Konar , Huili Xing , Debdeep Jena

Graphene monolayers are known to display domains of anisotropic friction with twofold symmetry and anisotropy exceeding 200 percent. This anisotropy has been thought to originate from periodic nanoscale ripples in the graphene sheet, which…

Owing to its array of unique properties, graphene is a promising material for a wide variety of applications. Being two-dimensional, the properties of graphene are also easily tuned via proximity to other materials. In this work, we…

Mesoscale and Nanoscale Physics · Physics 2021-11-09 Aleandro Antidormi , Aron W. Cummings

Anisotropic electronic transport is a possible route towards nanoscale circuitry design, particularly in two-dimensional materials. Proposals to introduce such a feature in patterned graphene have to date relied on large-scale structural…

Mesoscale and Nanoscale Physics · Physics 2018-12-07 Soren Schou Gregersen , Jose H. Garcia , Antti-Pekka Jauho , Stephan Roche , Stephen R. Power

The creation of pseudo-magnetic fields in strained graphene has emerged as a promising route to allow observing intriguing physical phenomena that would be unattainable with laboratory superconducting magnets. Scanning tunneling…

Graphene is an ideal material to study fundamental Coulomb- and phonon-induced carrier scattering processes. Its remarkable gapless and linear band structure opens up new carrier relaxation channels. In particular, Auger scattering bridging…

For many of the envisioned optoelectronic applications of graphene it is crucial to understand the sub-picosecond carrier dynamics immediately following photoexcitation, as well as the effect on the electrical conductivity - the…

We present a new paradigm for understanding optical absorption and hot electron dynamics experiments in graphene. Our analysis pivots on assigning proper importance to phonon assisted indirect processes and bleaching of direct processes. We…

Materials Science · Physics 2017-11-22 Yuan Yang , Grigory Kolesov , Lucas Kocia , Eric J. Heller

Exciting atomic oscillations with light is a powerful technique to control the electronic properties of materials, leading to remarkable phenomena such as light-induced superconductivity and ultrafast insulator to metal transitions. Here we…

Strongly Correlated Electrons · Physics 2021-05-13 D. Afanasiev , J. R. Hortensius , B. A. Ivanov , A. Sasani , E. Bousquet , Y. M. Blanter , R. V. Mikhaylovskiy , A. V. Kimel , A. D. Caviglia