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We report several quantum interference effects in graphene grown by chemical vapor deposition. A crossover between weak localization and weak antilocalization effects is observed when varying the gate voltage and we discuss the underlying…

Mesoscale and Nanoscale Physics · Physics 2023-07-19 Nam-Hee Kim , Yun-Sok Shin , Serin Park , Hong-Seok Kim , Jun Sung Lee , Chi Won Ahn , Jeong-O Lee , Yong-Joo Doh

We report on the observation of magnetoresistance oscillations in graphene p-n junctions. The oscillations have been observed for six samples, consisting of single-layer and bilayer graphene, and persist up to temperatures of 30 K, where…

Herein we discuss the fabrication of ballistic suspended graphene nanostructures supplemented with local gating. Using in-situ current annealing, we show that exceptional high mobilities can be obtained in these devices. A detailed…

Mesoscale and Nanoscale Physics · Physics 2014-09-17 Romain Maurand , Peter Rickhaus , Peter Makk , Samuel Hess , Endre Tovari , Clevin Handschin , Markus Weiss , Christian Schonenberger

Combining experiment and theory, we investigate how the naturally created heterojunction at a graphene and metallic contact is modulated via interaction with molecular hydrogen (H2). Due to electrostatic interaction, a Cr/Au electrode…

We investigate the influence of gauge fields induced by strain on the supercurrent passing through the graphene-based Josephson junctions. We show in the presence of a constant pseudomagnetic field ${\bf B}_S$ originated from an arc-shape…

Mesoscale and Nanoscale Physics · Physics 2018-11-21 Hadi Khanjani , Ali G. Moghaddam

We articulate the challenges and opportunities of unconventional devices using the photon like flow of electrons in graphene, such as Graphene Klein Tunnel (GKT) transistors. The underlying physics is the employment of momentum rather than…

Mesoscale and Nanoscale Physics · Physics 2019-03-01 Mirza M. Elahi , K. M. Masum Habib , Ke Wang , Gil-Ho Lee , Philip Kim , Avik W. Ghosh

With the advent of high mobility encapsulated graphene devices, new electronic components ruled by Dirac fermions optics have been envisioned and realized. The main building blocks of electron-optics devices are gate-defined p-n junctions,…

Superperiodic patterns were observed by STM on two kinds of finite-sized graphene sheets. One is nanographene sheets inclined from a highly oriented pyrolitic graphite (HOPG) substrate and the other is several-layer-thick graphene sheets…

Spatial manipulation of current flow in graphene could be achieved through the use of a tilted pn junction. We show through numerical simulation that a pseudo-Hall effect (i.e. non-equilibrium charge and current density accumulating along…

Mesoscale and Nanoscale Physics · Physics 2009-12-20 Tony Low , Joerg Appenzeller

At filling factor $\nu=0,\pm1$, the ground state of graphene is a particular SU(4) ferromagnet which hosts a rich phase diagram along with several spin, pseudospin or "entanglement" magnon modes. Motivated by recent experiments, we study a…

Mesoscale and Nanoscale Physics · Physics 2024-09-24 Jonathan Atteia , Preden Roulleau , Mark O. Goerbig

Four-terminal resistances, both longitudinal and diagonal, of a locally gated graphene device are measured in the quantum-Hall (QH) regime. In sharp distinction from previous two-terminal studies [J. R. Williams \textit{et al.}, Science…

Mesoscale and Nanoscale Physics · Physics 2012-03-05 Dong-Keun Ki , Hu-Jong Lee

Graphene is a stable single atomic layer material exhibiting two-dimensional electron gas of massless Dirac fermions of high mobility. One of the intriguing properties of graphene is a possibility of realization of the Tamm-type edge…

Mesoscale and Nanoscale Physics · Physics 2013-10-04 Yu. I. Latyshev , A. P. Orlov , V. A. Volkov , V. V. Enaldiev , I. V. Zagorodnev , O. F. Vyvenko , Yu. V. Petrov , P. Monceau

The longitudinal resistances of a six-terminal graphene p-n junction under a perpendicular magnetic field are investigated. Because of the chirality of the Hall edge states, the longitudinal resistances on top and bottom edges of the…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Jiang-chai Chen , T. C. Au Yeung , Qing-feng Sun

We introduce a new scheme to realize suspended, multi-terminal graphene structures that can be current annealed successfully to obtain uniform, very high quality devices. A key aspect is that the bulky metallic contacts are not connected…

Mesoscale and Nanoscale Physics · Physics 2014-01-17 Dong-Keun Ki , Alberto F. Morpurgo

Linear conductance of junctions formed by graphene flakes with order of nanometer-thick electrodes attached at the corners of the flakes is studied. The explored structures have sizes up to 20000 atoms and the conductance is studied as a…

Mesoscale and Nanoscale Physics · Physics 2015-10-08 Martin Konôpka

Using high quality graphene pnp junctions, we observe prominent conductance fluctuations on transitions between quantum Hall (QH) plateaus as the top gate voltage Vtg is varied. In the Vtg-B plane, the fluctuations form crisscrossing lines…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Jairo Velasco , Gang Liu , Lei Jing , Philip Kratz , Wenzhong Bao , Marc Bockrath , Chun Ning Lau

Q. Ma et al.[1] recently reported a strong photocurrent associated with charge neutrality in graphene devices with non-uniform geometries, which they interpreted as an intrinsic photoresponse enhanced by the momentum non-relaxing nature of…

Mesoscale and Nanoscale Physics · Physics 2020-02-26 Michael S. Fuhrer , Nikhil V. Medhekar

We measure the low-temperature resistance of permalloy break junctions as a function of contact size and the magnetic field angle, in applied fields large enough to saturate the magnetization. For both nanometer-scale metallic contacts and…

Mesoscale and Nanoscale Physics · Physics 2013-02-07 Kirill I. Bolotin , Ferdinand Kuemmeth , D. C. Ralph

The observation of quantum conductance oscillations in mesoscopic systems has traditionally required the confinement of the carriers to a phase space of reduced dimensionality. While electron optics such as lensing and focusing have been…

Mesoscale and Nanoscale Physics · Physics 2009-03-20 Andrea F. Young , Philip Kim

The intrinsic resistance peak (ridge) structures were recently found to appear in the carrier density dependence plot of the resistance of the AB-stacked multilayer graphene with even numbers of layers.The ridges are due to topological…

Mesoscale and Nanoscale Physics · Physics 2020-01-29 Tomoaki Nakasuga , Taiki Hirahara , Kota Horii , Ryoya Ebisuoka , Shingo Tajima , Kenji Watanabe , Takashi Taniguchi , Ryuta Yagi