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We present a study of the magnetoresistance of highly oriented pyrolytic graphite (HOPG) as a function of the sample size. Our results show unequivocally that the magnetoresistance reduces with the sample size even for samples of hundreds…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 J. C. González , M. Muñoz , N. García , J. Barzola-Quiquia , D. Spoddig , K. Schindler , P. Esquinazi

Carbon materials are attracting increasing attention due to the novelty of the associated physical properties and the potential applications in high-tech devices. The possibility to achieve outstanding properties in macroscopic carbon…

Discovery of superconductivity at megabar (MB) pressures in hydrogen sulfide H3S, then in metal polyhydrides, starting with binary, LaH10, etc., and ending with ternary ones, including (La, Y)H10, revolutionized the field of condensed…

Exposure of highly oriented pyrolytic graphite to bromine vapor gives rise to in-plane charge conductivities which increase monotonically with intercalation time toward values (for ~6 at% Br) that are significantly higher than Cu at…

Materials Science · Physics 2013-05-29 S. Tongay , J. Hwang , D. B. Tanner , H. K. Pal , D. Maslov , A. F. Hebard

Digital alloys of GaSb/Mn have been fabricated by molecular beam epitaxy. Transmission electron micrographs showed good crystal quality with individual Mn-containing layers well resolved; no evidence of 3D MnSb precipitates was seen in…

Materials Science · Physics 2009-11-07 X. Chen , M. Na , M. Cheon , S. Wang , H. Luo , B. D. McCombe , X. Liu , Y. Sasaki , T. Wojtowicz , J. K. Furdyna , S. J. Potashnik , P. Schiffer

Superconducting characteristics such as the Meissner-Ochsenfeld state, screening supercurrents and hysteresis loops of type-II superconductors were observed from the temperature and magnetic field dependences of the magnetic moment, m(T,…

Superconductivity · Physics 2009-11-07 S. Moehlecke , Pei-Chun Ho , M. B. Maple

We investigate the quasi-static magnetic behavior of ensembles of non-interacting ferromagnetic nanoparticles consisting of MnP nanoclusters embedded in GaP(001) epilayers grown at 600, 650 and 700{\deg}C. We use a phenomenological model,…

Materials Science · Physics 2016-03-23 Christian Lacroix , Samuel Lambert-Milot , Patrick Desjardins , Remo A. Masut , David Menard

This work deals with the intrinsic and extrinsic properties of the graphene layers inside the graphite structure, in particular the influence of defects and interfaces. We discuss the evidence for ballistic transport found in mesoscopic…

Materials Science · Physics 2011-10-13 J. Barzola-Quiquia , A. Ballestar , S. Dusari , P. Esquinazi

Within the BCS theory of superconductivity we calculate the superconducting gap at zero temperature for metallic hydrogen-graphene system in order to estimate the superconducting critical temperature of quasi two dimensional highly oriented…

Superconductivity · Physics 2009-02-11 N. García , P. Esquinazi

We study the superconducting phase transition, both in a graphene bilayer and in graphite. For that purpose we derive the mean-field effective potential for a stack of graphene layers presenting hopping between adjacent sheets. For…

Superconductivity · Physics 2020-10-05 Lizardo H. C. M. Nunes , E. C. Marino , A. L. Mota

Graphene field effect transistors commonly comprise graphene flakes lying on SiO2 surfaces. The gate-voltage dependent conductance shows hysteresis depending on the gate sweeping rate/range. It is shown here that the transistors exhibit two…

Mesoscale and Nanoscale Physics · Physics 2011-01-19 Haomin Wang , Yihong Wu , Chunxiao Cong , Jingzhi Shang , Ting Yu

Using non-equilibrium molecular dynamics (NEMD) simulation, we study thermal properties of the so-called nanoporous graphene (NPG) sheet which contains a series of nanoporous in an ordered way and was synthesized recently (Science 360…

Computational Physics · Physics 2021-07-29 Farrokh Yousefi , Farhad Khoeini , Ali Rajabpour

We have made thermal and electrical transport measurements of uncompressed pyrolytic graphite sheet (uPGS), a mass-produced thin graphite sheet with various thicknesses between 10 and 100 {\mu}m, at temperatures between 2 and 300 K.…

Materials Science · Physics 2017-10-04 Sachiko Nakamura , Daisuke Miyafuji , Takenori Fujii , Tomohiro Matsui , Hiroshi Fukuyama

Measurements of the basal-plane resistivity rho_a(T,H) performed on highly oriented pyrolitic graphite, with magnetic field H parallel to the c-axis in the temperature interval 2 - 300 K and fields up to 8 T, provide evidence for the…

Strongly Correlated Electrons · Physics 2009-11-07 Y. Kopelevich , V. V. Lemanov , S. Moehlecke , J. H. S. Torres

We present an extensive study on electrical spectroscopy of graphene ribbons and edges of highly oriented pyrolytic graphite (HOPG) using atomic force microscope (AFM). We have addressed in the present study two main issues, (1) How does…

Other Condensed Matter · Physics 2009-11-11 S. Banerjee , M. Sardar , N. Gayathri , A. K. Tyagi , Baldev Raj

We investigate the optical properties of bromine intercalated highly orientated pyrolytic graphite (Br-HOPG) and provide a novel interpretation of the data. We observe new absorption features below 620 meV which are absent in the absorption…

Materials Science · Physics 2016-11-25 J. Hwang , J. P. Carbotte , S. Tongay , A. F. Hebard , D. B. Tanner

We have studied the magnetotransport of conical and disk-shaped nanocarbon particles in magnetic fields $\left|B\right|\leq9\:\mathrm{T}$ at temperatures $2\leq T\leq300\:\mathrm{K}$ to characterize electron scattering in a three…

Mesoscale and Nanoscale Physics · Physics 2014-07-28 Jozef Černák , Geir Helgesen , Fredrik Sydow Hage , Jozef Kováč

We investigated the influence of thickness reduction on the transport properties of graphite microflakes. Using oxygen plasma etching we decreased the thickness of highly oriented pyrolytic graphite (HOPG) microflakes from $\sim 100$~nm to…

Hysteresis in resistance under magnetic field sweeps is a key signature for identifying magnetism in twisted bilayer graphene and similar systems. However, such sweeps can induce extrinsic thermal effects, complicating interpretations.…

Mesoscale and Nanoscale Physics · Physics 2025-04-10 Ranit Dutta , Ayan Ghosh , Kenji Watanabe , Takashi Taniguchi , Anindya Das

The pair-fluctuation contribution reduces the electrostatic screening length in superconductivity as compared to the normal state. When a conductor possesses a static background charge distribution, superconductivity arises even in the…

Superconductivity · Physics 2014-04-28 Kosuke Odagiri