Khuong Kim Huynh

High-quality three-dimensional nanoporous graphene.

We report three-dimensional (3D) nanoporous graphene with preserved 2D electronic properties, tunable pore sizes, and high electron mobility for electronic applications. The complex 3D network comprised of interconnected graphene retains a 2D coherent electron system of massless Dirac fermions. The transport properties of the nanoporous graphene show a semiconducting behavior and strong pore-size dependence, together with unique angular independence. The free-standing, large-scale nanoporous graphene with 2D electronic properties and high electron mobility holds great promise for practical applications in 3D electronic devices.

Both electron and hole Dirac cone states in Ba(FeAs)2 confirmed by magnetoresistance.

Quantum transport of Dirac cone states in the iron pnictide Ba(FeAs)(2) with a d-multiband system is studied by using single crystal samples. Transverse magnetoresistance develops linearly against the magnetic field at low temperatures. The transport phenomena are interpreted in terms of the zeroth Landau level by applying the theory predicted by Abrikosov. The results of the semiclassical analyses of a two carrier system in a low magnetic field limit show that both the electron and hole reside as the high mobility states. Our results show that pairs of electron and hole Dirac cone states must be taken into account for an accurate interpretation in iron pnictides, which is in contrast with previous studies.

Electric transport of a single-crystal iron chalcogenide FeSe superconductor: Evidence of symmetry-breakdown nematicity and additional ultrafast Dirac cone-like carriers

An SDW antiferromagnetic (SDW-AF) low temperature phase transition is generally observe and the AF spin fluctuations are considered to play an important role for the superconductivity paring mechanism in FeAs superconductors. However, a similar magnetic phase transition is not observed in FeSe superconductors, which has caused considerable discussion. We report on the intrinsic electronic states of FeSe as elucidated by transport measurements under magnetic fields using a high quality single crystal. A mobility spectrum analysis, an ab initio method that does not make assumptions on the transport parameters in a multicarrier system, provides very import and clear evidence that another hidden order, most likely the symmetry broken from the tetragonal C4 symmetry to the C2 symmetry nematicity associated with the selective d-orbital splitting, exists in the case of superconducting FeSe other than the AF magnetic order spin fluctuations. The intrinsic low temperature phase in FeSe is in the almost compensated semimetallic states but is additionally accompanied by Dirac cone like ultrafast electrons

In-plane topological p-n junction in the three-dimensional topological insulator Bi 2− x Sb x Te 3− y Se y

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Electric Properties of Dirac Fermions Captured into 3D Nanoporous Graphene Networks.

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Van der Waals epitaxial growth of topological insulator Bi2−xSbxTe3−ySey ultrathin nanoplate on electrically insulating fluorophlogopite mica

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Large-Area and Transferred High-Quality Three-Dimensional Topological Insulator Bi2–xSbxTe3–ySey Ultrathin Film by Catalyst-Free Physical Vapor Deposition

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Coexistence of Dirac-cone states and superconductivity in iron pnictide Ba(Fe1−xRuxAs)2

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Superconductivity pairing mechanism from cobalt impurity doping in FeSe: Spin (s.+-.) or orbital (s++) fluctuation

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Enhanced superconducting transition temperature in hyper-interlayer-expanded FeSe despite the suppressed electronic nematic order and spin fluctuations

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