| 1. |
- Bergqvist, Lars, 1976-, et al.
(författare)
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Magnetic and electronic structure of (Ga1-xMnx)As
- 2003
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 67:20, s. 205201-
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Tidskriftsartikel (refereegranskat)abstract
- We present theoretical calculations of the magnetic and electronic structure of Mn-doped GaAs (in the zinc-blende structure). The magnetic properties are shown to be very sensitive to structural defects, in particular, As antisite defects and Mn at interstitial positions. Only when considering such defects can the experimental magnetic moments be reproduced by first-principles theory. We present a simple model for understanding the connection between the magnetic ordering and the As antisites, and the way in which the defects help to stabilize a partial disordered local-moment state. The connection between the energetics of the Mn substitution and the As antisite concentration is also analyzed. In addition, we compare the calculated magnetic properties and electronic structures of Mn situated on substitutional sites (Mn replacing a Ga atom) and on interstitial sites, where in agreement with observations the interstitial site is found to be less favorable. Finally, combining our first-principles calculations of the spin-wave excitation energies with a classical Heisenberg Hamiltonian we have calculated interatomic exchange interactions, and using Monte Carlo simulations we present theoretical values of the critical temperature as a function of Mn concentration.
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| 2. |
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| 3. |
- Mulder F, Bouakaz L, Lundell A, Venkataramana M, Liljas A, Akke M and Sanyal S
(författare)
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Conformation and dynamics of ribosomal stalk protein L12 in solution and on the ribosome.
- 2004
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Ingår i: Biochemistry. ; 43:23
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Tidskriftsartikel (refereegranskat)abstract
- During translation, the ribosome and several of its constituent proteins undergo structural transitions between different functional states. Protein L12, present in four copies in prokaryotic ribosomes, forms a flexible “stalk” with key function in factor
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| 4. |
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| 5. |
- Chandra Sanyal, S, et al.
(författare)
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The end of the beginning: structural studies of ribosomal proteins
- 2000
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Ingår i: Curr Opin Struct Biol. ; 10:6, s. 633-636
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Recension (populärvet., debatt m.m.)abstract
- Work on the structural biology of ribosomes has progressed rapidly over the past few years. It has come to a stage at which the structures of the individual components are no longer of interest, except for those that still present ambiguous information ab
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| 6. |
- Eriksson, Olle, et al.
(författare)
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Electronic structure and magnetism of diluted magnetic semiconductors
- 2004
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 16:48, s. S5481-S5489
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure and magnetism of selected diluted magnetic semiconductors (DMS) is reviewed. It is argued that the effect of antisite defects plays an important role in the magnetism of DMS materials and that these defects lower the saturation moment and ordering temperature. We also show that the interatomic exchange of these materials is short ranged. By combining first principles calculations of interatomic exchange interactions with a classical Heisenberg model and Monte Carlo simulations, we show that-the observed critical temperatures of a broad range of diluted magnetic semiconductors, involving Mn-doped GaAs and GaN as well as Cr-doped ZnTe, are reproduced with good accuracy. We show that agreement between theory and experiment is obtained only when the magnetic atoms are randomly positioned on the Ga (or Zn) sites. This suggests that the ordering of DMS materials is heavily influenced by magnetic percolation and that the measured critical temperatures should be very sensitive to details in the sample preparation, in agreement with observations.
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| 7. |
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| 8. |
- Ghosh, S., et al.
(författare)
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Electronic structure and magnetism of disordered bcc Fe alloys
- 2001
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Ingår i: European Physical Journal B. - : Springer Science and Business Media LLC. - 1434-6028 .- 1434-6036. ; 23:4, s. 455-461
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Tidskriftsartikel (refereegranskat)abstract
- We study the electronic structure and magnetic properties of disordered bcc CoxFe1-x, CrxFe1-x and MnxFe1-x alloys in their ferromagnetic phases using the Augmented Space Recursion (ASR) technique coupled with the tight-binding linearized muffin tin orbital (TB-LMTO) method. We calculate the density of states and magnetic moment of these alloys to show the variation upon alloying Fe with the other neighbouring 3d transition metals using arguments based on charge transfer, exchange splitting and hybridization effects.
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| 9. |
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