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The magnetic circular dichroism of III-V diluted magnetic semiconductors, calculated within a theoretical framework suitable for highly disordered materials, is shown to be dominated by optical transitions between the bulk bands and an…

Materials Science · Physics 2008-10-12 Jian-Ming Tang , Michael E. Flatte

Magnetic impurities adsorbed on graphene are coupled magnetically via the itinerant electrons. This interaction opens a gap in the band structure of graphene. The result strongly depends on how the magnetic impurities are distributed. While…

Strongly Correlated Electrons · Physics 2010-10-05 Maria Daghofer , Nan Zheng , Adriana Moreo

It is well-known that the Curie temperature, and hence the magnetization, in diluted magnetic semiconductor (DMS) like Ga$_{1-x}$Mn$_x$As can be controlled by changing the equilibrium density of holes in the material. Here, we propose that…

Mesoscale and Nanoscale Physics · Physics 2010-05-04 L. Siddiqui , A. N. M. Zainuddin , S. Datta

The presence of localized spins exerts a strong influence on quantum localization in doped semiconductors. At the same time carrier-mediated interactions between the localized spins are modified or even halted by carriers' localization. The…

Disordered Systems and Neural Networks · Physics 2008-10-20 Tomasz Dietl

We present a detailed study, within the mean-field approximation, of an impurity band model for III-V diluted magnetic semiconductors. Such a model should be relevant at low carrier densities, below and near the metal-insulator transition.…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Mona Berciu , R. N. Bhatt

We report results of a Monte Carlo study of doped, diluted magnetic semiconductors in the low carrier density (insulating) regime. We find that the system undergoes a transition from a paramagnet at high temperatures to a ferromagnet at low…

Materials Science · Physics 2007-05-23 Xin Wan , R. N. Bhatt

Density functional calculations are performed to study the magnetic order of the severely distorted square planar cupric oxide (CuO) and local spin disorder in it in the presence of the transition metal impurities M (= Cr, Mn, Fe, Co and…

Strongly Correlated Electrons · Physics 2017-04-05 B. G. Ganga , P. N. Santhosh , B. R. K. Nanda

We study the spin and charge dynamics of electrons in n-doped II--VI semiconductor multiple quantum wells when one or more quantum wells are doped with Mn. The interplay between strongly nonlinear inter-well charge transport and the large…

Condensed Matter · Physics 2009-11-07 Manuel Bejar , David Sanchez , Gloria Platero , A. H. MacDonald

Although the creation of spin polarization in various non-magnetic media via electrical spin injection from a ferromagnetic tunnel contact has been demonstrated, much of the basic behavior is heavily debated. It is reported here for…

Mesoscale and Nanoscale Physics · Physics 2015-03-17 S. P. Dash , S. Sharma , J. C. Le Breton , H. Jaffrès , J. Peiro , J. -M. George , A. Lemaître , R. Jansen

A fundamental connection between superconductivity and quantum spin fluctuations in underdoped cuprates, is revealed. A variational calculation shows that {\em Cooper pair hopping} strongly reduces the local magnetization $m_0$. This effect…

Strongly Correlated Electrons · Physics 2009-10-31 Moshe Havilio , Assa Auerbach

We derive an effective Hamiltonian for ${\rm Ga}_{1-x}{\rm Mn}_x {\rm As}$ in the dilute limit, where ${\rm Ga}_{1-x}{\rm Mn}_x {\rm As}$ can be described in terms of spin $F=3/2$ polarons hopping between the {\rm Mn} sites and coupled to…

Materials Science · Physics 2007-05-23 Gregory A. Fiete , Gergely Zarand , Kedar Damle , C. Pascu Moca

We consider a spin-orbit coupled particle confined in a quantum dot in a bath of impurity spins. We investigate the consequences of spin-orbit coupling on the interactions that the particle mediates in the spin bath. We show that in the…

Mesoscale and Nanoscale Physics · Physics 2014-09-02 Peter Stano , Jaroslav Fabian , Igor Žutić

We investigate the enhancement of spin polarization in a quantum wire in the presence of a constriction and a spin-orbit coupling segment. It is shown that the spin-filtering effect is significantly heightened in comparison with the…

Mesoscale and Nanoscale Physics · Physics 2008-10-07 Jun-Feng Liu , Zhi-Cheng Zhong , Lei Chen , Dingping Li , Chao Zhang , Zhongshui Ma

We study the effect of magnetic scattering on transport in a system with strong structural disorder, using exact finite size calculation of the low frequency optical conductivity. At weak electron-spin coupling spin disorder leads to a…

Disordered Systems and Neural Networks · Physics 2009-11-10 Sanjeev Kumar , Pinaki Majumdar

The influence of configurational disorder on the magnetic properties of diluted Heisenberg spin systems is studied with regard to the ferromagnetic stability of diluted magnetic semiconductors. The equation of motion of the magnon Green's…

Disordered Systems and Neural Networks · Physics 2015-06-25 Guixin Tang , Wolfgang Nolting

We study a magnetic impurity embedded in a correlated electron system using the density-matrix renormalization group method. The correlated electron system is described by the one-dimensional Hubbard model. At half filling, we confirm that…

Strongly Correlated Electrons · Physics 2007-05-23 S. Nishimoto , P. Fulde

We calculate the density-of-states and the spectral function of GaMnAs within the dynamical mean-field approximation. Our model includes the competing effects of the strong spin-orbit coupling on the J=3/2 GaAs hole bands and the exchange…

Strongly Correlated Electrons · Physics 2009-11-11 M. A. Majidi , J. Moreno , M. Jarrell , R. S. Fishman , K. Aryanpour

We present a theory of magnetic (Ni) and nonmagnetic (Zn) impurities substituted into planar Cu sites in the normal state of underdoped cuprates exhibiting a spin gap. Both types of impurities induce magnetic moments on neighboring Cu…

Strongly Correlated Electrons · Physics 2009-10-31 G. Khaliullin , R. Kilian , S. Krivenko , P. Fulde

It is shown that spin Hall effect creates uniform spin polarization of electrons in semiconductor with a linear in the momentum spin splitting of conduction band. In turn, the profile of the non-uniform spin polarization accumulated at the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 V. L. Korenev

We examine and identify magnetoresistance mechanisms in 2D system containing a sizable concentration of magnetic ions. We argue that some of these mechanisms can serve as a tool to measure spin polarization. Lack of spin degeneracy and…