Detection of stacking faults breaking the [110]/[1<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mover accent="true"><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:mo>¯</mml:mo></mml:mrow></mml:mover></mml:mrow></mml:math>0] symmetry in ferromagnetic semiconductors (Ga,Mn)As and (Ga,Mn)(As,P)

Kopecký, M.; Kub, J.; Máca, F.; Mašek, J.; Pacherová, O.; Rushforth, A. W.; Gallagher, B. L.; Campion, R. P.; Novák, V.; Jungwirth, T.

doi:10.1103/physrevb.83.235324

Cited by 26 publications

(19 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among many consequences of such a non-random Mn distribution is the appearance of a local strain, as Mn atoms in the pair are displaced of the GaAs cation positions, whereas the As atom between them is shifted along the [001] direction by as much as 2.6% of the bond length. The resulting strain may contribute to the formation of stacking faults propagating in the (111) and (111) planes [26], observed in (Ga,Mn)As by high resolution electron transmission microscopy [27] and synchrotron xray diffraction [28]. Importantly, according to recent ab initio studies [28], the intersection lines of the stacking fault pairs may enhance further the aggregation of Mn dimers along the [110] crystallographic directions.…”

mentioning

confidence: 99%

Origin of Bulk Uniaxial Anisotropy in Zinc-Blende Dilute Magnetic Semiconductors

et al. 2012

View full text Add to dashboard Cite

It is demonstrated that the nearest-neighbor Mn pair on the GaAs (001) surface has a lower energy for the [110] direction compared to the [110] case. According to the group theory and Luttinger's method of invariants, this specific Mn distribution results in bulk uniaxial in-plane and out-of-plane anisotropies. The sign and magnitude of the corresponding anisotropy energies determined by a perturbation method and ab initio computations are consistent with experimental results.

show abstract

mentioning

confidence: 99%

Origin of Bulk Uniaxial Anisotropy in Zinc-Blende Dilute Magnetic Semiconductors

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Recently, Werpachowska and Dietl 22 suggested that the anisotropy mechanism in (Ga,Mn)As films originates from Dzyaloshinsky-Moriya interactions, without assuming any in-plane lattice distortion within their model. Another group of authors have found in the experiment 23 the stacking fault defects in the (111) and (111) planes, which could be responsible for breaking the equivalence of the [110] and [110] directions in the (Ga,Mn)As films. However, to the best of our knowledge, there is so far no experimental evidence nor theoretical description showing that these stacking faults are responsible for the in-plane uniaxial anisotropy.…”

mentioning

confidence: 99%

Spin-orbit coupling effect in (Ga,Mn)As films: Anisotropic exchange interactions and magnetocrystalline anisotropy

et al. 2011

View full text Add to dashboard Cite

The magnetocrystalline anisotropy (MCA) of (Ga,Mn)As films has been studied on the basis of ab initio electronic structure theory by performing magnetic torque calculations. An appreciable contribution to the in-plane uniaxial anisotropy can be attributed to an extended region adjacent to the surface. Calculations of the exchange tensor allow to ascribe a significant part to the MCA to the exchange anisotropy, caused either by a tetragonal distortion of the lattice or by the presence of the surface or interface. Diluted magnetic semiconductors (DMSs) are a class of materials having attractive properties for spintronic applications (e.g., see the review in Ref. 1). Many investigations in this field are focused on the (Ga,Mn)As DMS system with 1%-10% of Mn atoms which have promising features from a physical as well as technological point of view. The crucial role of valence states with respect to various magnetic properties of (Ga,Mn)As was discussed in the literature by many authors (e.g., Refs. 1-5, and 6). First of all, the valence-band holes are responsible for ferromagnetic (FM) order in the system mediating the exchange interaction between well-localized Mn magnetic moments. Spin-orbit coupling of the states at the top of valence band, being close to the Fermi level, leads to a rather strong cubic magnetocrystalline anisotropy (MCA) in bulk (Ga,Mn)As and to an in-plane biaxial MCA in the (Ga,Mn)As film on top of a GaAs substrate. [1][2][3] In the latter case the spin-orbit coupling (SOC) makes the valence states close to E F sensitive to lattice distortions and is in that way responsible for the in-plane MCA due to compressive strains originating from the lattice mismatch between the (Ga,Mn)As film and GaAs substrate. [7][8][9][10][11][12][13][14][15][16][17] As soon as the spin polarization of the valence bands becomes rather small, the MCA in (Ga,Mn)As is discussed in terms of anisotropic exchange interactions of the Mn atoms. 2,3,7 The strength of the MCA depends on the hole concentration introduced by the Mn impurity atoms 2,11,18,19 as well as on the variation of the equilibrium lattice parameter of (Ga,Mn)As, which increases with increasing Mn content and results thus in a larger lattice mismatch with the GaAs substrate.Numerous experimental results evidenced a temperature-induced transition from the biaxial to the uniaxial in-plane anisotropy in (Ga,Mn)As films deposited on GaAs. [11][12][13][14][15][16][17][18] In spite of different experimental conditions, the in-plane uniaxial anisotropy was observed for (Ga,Mn)As films in a thickness range from 25 nm (Ref. 20) to 500 nm, 16 irrelevant with respect to the surface condition. So far, however, to the best of our knowledge, there is no consensus in the literature concerning the origin of the in-plane uniaxial anisotropy. Although in some recent theoretical works the origin of the uniaxial in-plane anisotropy is attributed to a trigonal distortion caused by a uniaxial or shear strain within the film plane, 13,18,21 this type of distortion was not obser...

show abstract

“…Such behaviour, with the direction being magnetically easier than the perpendicular [110] one, is characteristic of compressively strained (Ga,Mn)As layers with high concentration of valence-band holes 9,21 . The origin of the uniaxial in-plane anisotropy is still debated 22–24 and most probably results from the preferred formation of Mn dimmers along the crystallographic direction at the (001) surface during the epitaxial growth of (Ga,Mn)As layers, as concluded from the recent ab initio calculations 25 . The (Ga,Mn)As and (Ga,Mn)(Bi,As) layers are characterized by the T C values of about 105 K and 90 K, respectively, as evaluated from the temperature dependences of SQUID magnetization shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Evidence for the homogeneous ferromagnetic phase in (Ga,Mn)(Bi,As) epitaxial layers from muon spin relaxation spectroscopy

Levchenko

Prokscha

Sadowski

et al. 2019

Sci Rep

View full text Add to dashboard Cite

Ferromagnetic semiconductor thin layers of the quaternary (Ga,Mn)(Bi,As) and reference, ternary (Ga,Mn)As compounds, epitaxially grown under either compressive or tensile strain, have been characterized from a perspective of structural and magnetization homogeneity. The quality and composition of the layers have been confirmed by secondary-ion mass spectrometry (SIMS). A thorough evaluation of the magnetic properties as a function of temperature and applied magnetic field has been performed by means of SQUID magnetometry and low-energy muon spin relaxation (µSR) spectroscopy, which enables studying local (on the nanometer scale) magnetic properties of the layers. The results testify that the ferromagnetic order builds up almost homogeneously below the Curie temperature in the full volume fraction of both the (Ga,Mn)As and (Ga,Mn)(Bi,As) layers. Incorporation of a small amount of heavy Bi atoms into (Ga,Mn)As, which distinctly enhances the strength of spin-orbit coupling in the quaternary (Ga,Mn)(Bi,As) layers, does not deteriorate noticeably their magnetic properties.

show abstract

Detection of stacking faults breaking the [110]/[11¯0] symmetry in ferromagnetic semiconductors (Ga,Mn)As and (Ga,Mn)(As,P)

Cited by 26 publications

References 13 publications

Origin of Bulk Uniaxial Anisotropy in Zinc-Blende Dilute Magnetic Semiconductors

Origin of Bulk Uniaxial Anisotropy in Zinc-Blende Dilute Magnetic Semiconductors

Spin-orbit coupling effect in (Ga,Mn)As films: Anisotropic exchange interactions and magnetocrystalline anisotropy

Evidence for the homogeneous ferromagnetic phase in (Ga,Mn)(Bi,As) epitaxial layers from muon spin relaxation spectroscopy

Contact Info

Product

Resources

About