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We investigate the effects of a magnetic impurity in a multiband touching fermion system, specifically, a triple-component semimetal with a flat band, which can be realized in a family of transition metal silicides (CoSi family). When the…

Strongly Correlated Electrons · Physics 2020-11-21 Yu-Li Lee , Yu-Wen Lee

Quantum interference effects and resulting quantum corrections of the conductivity have been intensively studied in disordered conductors over the last decades. The knowledge of phase coherence lengths and underlying dephasing mechanisms…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 D. Neumaier , K. Wagner , U. Wurstbauer , M. Reinwald , W. Wegscheider , D. Weiss

We have investigated the electronic structure of the $p$-type diluted magnetic semiconductor In$_{1-x}$Mn$_x$As by photoemission spectroscopy. The Mn 3$d$ partial density of states is found to be basically similar to that of…

Materials Science · Physics 2016-08-31 J. Okabayashi , T. Mizokawa , D. D. Sarma , A. Fujimori , T. Slupinski , A. Oiwa , H. Munekata

We report ultrafast transient-grating measurements, above and below the Curie temperature, of the dilute ferromagnetic semiconductor (Ga,Mn)As containing 6% Mn. At 80 K (15 K), we observe that photoexcited electrons in the conduction band…

We propose a concept of superconductivity controlled by orbital degree of freedom taking CeMIn5 (M= Co, Rh, and Ir) as typical examples. A microscopic multiorbital model for CeMIn5 is analyzed by fluctuation exchange approximation. Even…

Superconductivity · Physics 2009-08-11 Katsunori Kubo , Takashi Hotta

Wurtzite GaN:Mn films on sapphire substrates were successfully grown by use of the molecular beam epitaxy (MBE) system. The film has an extremely high Curie temperature of around 940 K, although the Mn concentration is only about 3 ~ 5 %.…

Materials Science · Physics 2009-11-07 H. Hori , S. Sonoda , T. Sasaki , Y. Yamamoto , S. Shimizu , K. Suga , K. Kindo

We analyze the energy band structure of a two-dimensional electron gas in a periodic magnetic field of a longitudinal antiferromagnet by considering a simple exactly solvable model. Two types of states appear: with a finite and…

Condensed Matter · Physics 2009-10-28 Andrey Krakovsky

Nitrogen vacancy doped SmN$_{1-\delta}$ is a semiconductor which lies in the intermediary between insulating-ferromagnetic SmN and metallic-anti-ferromagnetic Sm. The dopant electrons resulting from nitrogen vacancies have recently been…

Superconductivity · Physics 2023-02-14 W. F. Holmes-Hewett , K. Van Koughnet , J. D. Miller , B. J. Ruck , H. J. Trodahl , R. G. Buckley

We theoretically investigate a possible idea to introduce magnetic impurities to a superfluid Fermi gas. In the presence of population imbalance ($N_\uparrow>N_\downarrow$, where $N_\sigma$ is the number of Fermi atoms with pseudospin…

Other Condensed Matter · Physics 2015-05-27 Yoji Ohashi

We provide experimental evidence that the upper limit of ~110 K commonly observed for the Curie temperature T_C of Ga(1-x)Mn(x)As is caused by the Fermi-level-induced hole saturation. Ion channeling, electrical and magnetization…

Materials Science · Physics 2009-11-10 K. M. Yu , W. Walukiewicz , T. Wojtowicz , W. L. Lim , X. Liu , U. Bindley , M. Dobrowolska , J. K. Furdyna

We consider the far-infrared and the microwave conductivities of a two-band superconductor with non-magnetic impurities. The strong coupling expressions for the frequency and temperature dependent conductivity of a two-band superconductor…

Superconductivity · Physics 2015-05-13 Bozidar Mitrovic

Presence of magnetism in potentially altermagnetic RuO$_2$ has been a subject of intense debate. Using broadband infrared spectroscopy combined with density-functional band-structure calculations, we show that optical conductivity of…

This article is a review o over theory of superconductivity, which is constructed for systems with two overlapping energy bands at the Fermi surface and with arbitrary charge carrier density.There is taken into account all possible kinds of…

Superconductivity · Physics 2007-05-23 M. E. Palistrant

We show that by introducing isoelectronic iron (Fe) magnetic impurities and Beryllium (Be) double-donor atoms into InAs, it is possible to grow a n-type ferromagnetic semiconductor (FMS) with the ability to control ferromagnetism by both Fe…

Defects in semiconductors, traditionally seen as detrimental to electronic device performance, have emerged as potential assets in quantum technologies due to their unique quantum properties. This study investigates the interaction between…

Mesoscale and Nanoscale Physics · Physics 2024-07-19 Motoya Shinozaki , Takaya Abe , Kazuma Matsumura , Takumi Aizawa , Takashi Kumasaka , Tomohiro Otsuka

MnAs/GaAs superlattices, made by $\delta$-doping GaAs with Mn, are known as digital ferromagnetic heterostructures. Here we present a theoretical density functional study of the electronic, magnetic and transport properties of such…

Materials Science · Physics 2009-11-07 Stefano Sanvito , Nicola A. Hill

We report the electronic structure of the iron-chalcogenide superconductor, Fe1.04(Te0.66Se0.34), obtained with high resolution angle-resolved photoemission spectroscopy and density functional calculations. In photoemission measurements,…

Within the model of elastic impurity scattering, we study how changes in the energy dependence of the electronic density of states (EDOS) $N(\epsilon)$ around the Fermi energy $\epsilon_F$ are reflected in the frequency-dependent optical…

Superconductivity · Physics 2009-11-07 Mei-Rong Li , J. P. Carbotte

The Fermi surfaces of Fe-pnictide superconductors are fairly two-dimensional (2D), and it has thus come as a surprise that recent penetration depth and thermal conductivity measurements on systems of the 122 type have reported c-axis…

Superconductivity · Physics 2015-03-18 V. Mishra , S. Graser , P. J. Hirschfeld

Magnetoelectric multiferroic composite of two types of multiferroic (Type I and II) consisting BiFeO3 and TbMnO3 is studied for enhanced magnetic and transport properties. A narrower band gap is estimated from the UV-visible absorption…