You are here

Recent Graphene Papers from APS

Contactless Microwave Characterization of Encapsulated Graphene p−n Junctions

Physical Review: Graphene - Wed, 24/05/2017 - 10:00pm

Author(s): V. Ranjan, S. Zihlmann, P. Makk, K. Watanabe, T. Taniguchi, and C. Schönenberger

The electrical contacts needed for conventional probing of a graphene-based device can mask the very properties to be measured. The authors demonstrate a contactless measurement scheme that capacitively couples a device to a superconducting microwave resonator. Both quantum capacitance and charge-relaxation resistance can be inferred from a single measurement, and residual doping and the Fermi velocity can be quantitatively deduced. This technique offers fast, sensitive, noninvasive measurement of graphene nanocircuits, or other systems for which ohmic contacts are difficult to obtain.

[Phys. Rev. Applied 7, 054015] Published Wed May 24, 2017

Suppression of supercollision carrier cooling in high mobility graphene on SiC(0001 [over ¯] )

Physical Review: Graphene - Wed, 19/04/2017 - 10:00pm

Author(s): Takashi Someya, Hirokazu Fukidome, Hiroshi Watanabe, Takashi Yamamoto, Masaru Okada, Hakuto Suzuki, Yu Ogawa, Takushi Iimori, Nobuhisa Ishii, Teruto Kanai, Keiichiro Tashima, Baojie Feng, Susumu Yamamoto, Jiro Itatani, Fumio Komori, Kozo Okazaki, Shik Shin, and Iwao Matsuda

Graphene, a two-dimensional monatomic layer of crystal carbon, has recently emerged as a potential material for next-generation optoelectronic devices owing to unique properties arising from its massless Dirac fermions. However, the intrinsic carrier dynamics of graphene has remained a mystery even for the simple case of carrier cooling after the photoexcitation. This is because the observed temporal variations of the nonequilibrium carriers in graphene have been thoroughly described in terms of a defect-induced extrinsic effect known as “supercollision” (SC). The SC process is based on defect-mediated electron-acoustic phonon scattering and theoretically has been predicted to reduce with the increase of mobility of a material. Here, the authors have prepared extremely high mobility graphene and traced the dynamics of photoexcited carriers in the Dirac bands directly by time- and angle-resolved photoemission spectroscopy. They successfully observed suppression of SC and extracted the intrinsic dynamical properties of graphene, such as anharmonic decay of the optical phonons and the bottleneck relaxation at the Dirac point. Breaking the limit of SC, their research also has technological significance in developing graphene-based optoelectronic devices.

[Phys. Rev. B 95, 165303] Published Wed Apr 19, 2017

Floquet Majorana fermions and parafermions in driven Rashba nanowires

Physical Review: Graphene - Thu, 06/04/2017 - 10:00pm

Author(s): Manisha Thakurathi, Daniel Loss, and Jelena Klinovaja

We study a periodically driven nanowire with Rashba-like conduction and valence bands in the presence of a magnetic field. We identify topological regimes in which the noninteracting system hosts zero-energy bound states. We further investigate the effect of strong electron-electron interactions tha…

[Phys. Rev. B 95, 155407] Published Thu Apr 06, 2017

Thermal Transport in Supported Graphene: Substrate Effects on Collective Excitations

Physical Review: Graphene - Tue, 28/03/2017 - 10:00pm

Author(s): Arthur France-Lanord, Patrick Soukiassian, Christian Glattli, and Erich Wimmer

Graphene’s exceptional thermal conductivity is of great interest for heat management in advanced electronic devices, yet there are still fundamental issues regarding substrate effects. Using state-of-the-art simulations, the authors study collective phonon excitations in graphene on on partially hydroxylated silica surfaces, and show that certain vibrational modes can be influenced to increase thermal conductivity beyond that seen with an untreated substrate. This insight opens a path for systematic control of heat flow in this important system.

[Phys. Rev. Applied 7, 034030] Published Tue Mar 28, 2017

Theory of graphene saturable absorption

Physical Review: Graphene - Mon, 06/03/2017 - 11:00pm

Author(s): A. Marini, J. D. Cox, and F. J. García de Abajo

Saturable absorption is a nonperturbative 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 opening avenues to new nonlinear physics and applications in …

[Phys. Rev. B 95, 125408] Published Mon Mar 06, 2017

Theme inspired by Danetsoft