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This work investigates the behavior of impurities in edge plasma of tokamaks using high-resolution numerical simulations based on Hasegawa--Wakatani equations. Specifically, it focuses on the behavior of inertial particles, which has not…

We have theoretically investigated thermoelectric (TE) effects of narrow-gap single-walled carbon nanotubes (SWCNTs) with randomly substituted nitrogen (N) impurities, i.e., N-substituted (20,0) SWCNTs with a band gap of 0.497 eV. For such…

Mesoscale and Nanoscale Physics · Physics 2021-03-16 Manaho Matsubara , Kenji Sasaoka , Takahiro Yamamoto , Hidetoshi Fukuyama

High quality p-type PbTe-CdTe monocrystalline alloys containing up to 10 at.$\%$ of Cd are obtained by self-selecting vapor transport method. Mid infrared photoluminescence experiments are performed to follow the variation of the…

Non-magnetic impurities in iron-based superconductors can provide an important tool to understand the pair symmetry and they can influence significantly the transport and the superconducting behaviour. Here, we present a study of the role…

Superconductivity · Physics 2022-04-12 Z. Zajicek , S. J. Singh , H. Jones , P. Reiss , M. Bristow , A. Martin , A. Gower , A. McCollam , A. I. Coldea

Roles of multipole degrees of freedom in multiband superconductors are investigated in a case of impurities whose low-lying states consist of singlet ground and triplet excited states, which is related to the experimental fact that the…

Strongly Correlated Electrons · Physics 2015-05-27 Mikito Koga , Masashige Matsumoto , Hiroaki Kusunose

We investigate in-gap states emerging when a single $3d$ transition metal impurity is embedded in topological insulators (Bi$_2$Te$_3$ and Bi$_2$Se$_3$). We use a combined approach relying on first-principles calculations and an Anderson…

Materials Science · Physics 2018-07-25 Juba Bouaziz , Manuel dos Santos Dias , Julen Ibañez-Azpiroz , Samir Lounis

Intervalley collisions, which scatter electrons from one valley or band to another, can be detrimental to thermoelectric performance in materials with multiple valleys/bands. In this study, density functional theory is used to investigate…

Materials Science · Physics 2023-02-08 Vahid Askarpour , Jesse Maassen

The influence of individual impurities of Fe on the electronic properties of topological insulator Bi$_2$Se$_3$ is studied by Scanning Tunneling Microscopy. The microscope tip is used in order to remotely charge/discharge Fe impurities. The…

Recently discovered high-T$_c$ superconductivity in pressurized bilayer nickelate La$_3$Ni$_2$O$_7$ (La-327) is believed to be driven by the non-phononic repulsive interaction. Depending on the strength of the interlayer repulsion, the…

Superconductivity · Physics 2025-04-15 Steffen Bötzel , Frank Lechermann , Takasada Shibauchi , Ilya M. Eremin

We theoretically consider the effects of having unintentional charged impurities in laterally coupled two-dimensional double (GaAs) quantum dot systems, where each dot contains one or two electrons and a single charged impurity in the…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Nga T. T. Nguyen , S. Das Sarma

We consider a double-layer system made of two parallel bilayer graphene sheets separated by a dielectric medium. We calculate the finite-temperature electrical conductivity of the first layer due to charged impurities located in two layers.…

Mesoscale and Nanoscale Physics · Physics 2021-03-09 Dang Khanh Linh , Nguyen Quoc Khanh

Materials with ring-shaped electronic bands are promising thermoelectric candidates, since their unusual dispersion shape is predicted to give large power factors. While previous calculations of these materials have relied on the assumption…

Mesoscale and Nanoscale Physics · Physics 2021-04-14 Cameron Rudderham , Jesse Maassen

The impurity effects are studied for the BiS_{2}- layered superconductors based on a two orbital model with the Bogoliubov-de-Gennes technique. The superconducting critical temperature (T_{c}) as a function of the mpurity concentration is…

Superconductivity · Physics 2013-10-29 S. L. Liu

Infrared transparent conductors have long been sought due to their broad optoelectronic applications in the infrared wavelength range. However, the search for ideal materials has been limited by the inherent trade-off between electrical…

A two-band model with repulsive interband coupling and interband {\it transport} (potential) scattering is considered to elucidate their effects on material properties. In agreement with previous work, we find that the bands order…

Superconductivity · Physics 2016-06-22 V. G. Kogan , R. Prozorov

We study theoretically the effects of random nonmagnetic impurities on the superconducting transition temperature $T_c$ in a two-band superconductor characterized by an equal-time s-wave interband pairing order parameter. The Fermi-Dirac…

Superconductivity · Physics 2020-07-21 Yasuhiro Asano , Akihiro Sasaki , Alexander A. Golubov

Topological insulators represent a new state of quantum matter attractive to both fundamental physics and technological applications such as spintronics and quantum information processing. In a topological insulator, the bulk energy gap is…

We study the superfluid density of the $\pm$s-wave state of the minimal two band model for the Fe-based superconductors and its evolution with impurity concentration. We show that the impurity scattering of the strong coupling limit induces…

Superconductivity · Physics 2009-11-13 Yunkyu Bang

The two-gap model for superconductivity in MgB2 predicts that interband impurity scattering should be pair breaking, reducing the critical temperature. This is perhaps the only prediction of the model that has not been confirmed…

Superconductivity · Physics 2009-11-10 Steven C. Erwin , I. I. Mazin

We review the progress of nonmagnetic impurity doping study on the Fe-based superconductors. On the theoretical side, two highly potential candidates for the pairing symmetry order parameter, i.e. the multi-gap s++ and s+- wave models, have…