Positron annihilation and Fermi surface studies: a new approach

Lock, Duncan; Crisp, V.H.C.; West, R N

doi:10.1088/0305-4608/3/3/014

Cited by 292 publications

(135 citation statements)

References 20 publications

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“…where G is a reciprocal lattice vector and n Ϫ (r,k) is the density of the occupied electronic states at k. If the positron density n ϩ and the enhancement factor ␥ are constants, one obtains the electron momentum distribution in the first Brillouin zone ͑the Lock-Crisp-West theorem 33 ͒. In the case of metals, this distribution consists of occupied valence-state regions with a certain constant density separated by the socalled Fermi-surface breaks from the unoccupied valencestate regions with a lower density.…”

Section: ͑8͒mentioning

confidence: 99%

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Calculation of positron states and annihilation in solids: A density-gradient-correction scheme

et al. 1996

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The generalized gradient correction method for positron-electron correlation effects in solids ͓B. Barbiellini et al., Phys. Rev. B 51, 7341 ͑1995͔͒ is applied in several test cases. The positron lifetime, energetics, and momentum distribution of the annihilating electron-positron pairs are considered. The comparison with experiments shows systematic improvement in the predictive power of the theory compared to the local-density approximation results for positron states and annihilation characteristics. ͓S0163-1829͑96͒03824-6͔

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Section: ͑8͒mentioning

confidence: 99%

“…Moreover, the LCW theorem 33 proposes that when the 2D ACAR spectrum is folded into the first Brillouin zone, mainly the structures related to the FS remain. In some cases, the FS breaks can be inferred just by studying the occupation of the bands crossing the Fermi energy.…”

Section: D Acar Spectramentioning

confidence: 99%

Calculation of positron states and annihilation in solids: A density-gradient-correction scheme

et al. 1996

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“…Tomographic methods can be used to reconstruct the 3D momentum density from a series of measured projections [17]. While the momentum density is a single-centered distribution having the full point-symmetry of the crystal lattice in question, the translational invariance of k space can be restored by ''folding'' the distribution back into the first Brillouin zone (BZ), giving the 3D occupation density [18]. This technique has recently been used to determine the FS topology and identify nesting features in a wide range of systems [19].…”

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confidence: 99%

Direct Observation of the Multisheet Fermi Surface in the Strongly Correlated Transition Metal CompoundZrZn2

et al. 2004

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The existence of flat areas of a Fermi surface (FS), predicted by electronic structure calculations and used in models of both magnetically mediated and phonon-mediated Fulde-Ferrell-LarkinOvchinnikov superconducting states, is reported in the paramagnetic phase of the ferromagnetic superconductor ZrZn 2 using positron annihilation. The strongly mass-renormalized FS sheet, dominating the Fermi level density of states, is seen for the first time. The delocalization of the magnetization is studied using measured and calculated magnetic Compton profiles.

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“…The recorded ACAR spectra were corrected for the momentum sampling function and then folded back to k-space following the LCW-procedure [12]. This way features in the projection of the momentum distribution attributed to the Fermi surface are enhanced and easier to identify.…”

Section: Methodsmentioning

confidence: 99%

First measurements with the Munich 2D-ACAR spectrometer on Cr

Ceeh

Weber

Hugenschmidt

et al. 2013

J. Phys.: Conf. Ser.

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Abstract. The Munich 2D-ACAR spectrometer at the Maier-Leibnitz accelerator laboratory in Garching has recently become operational. In the present implementation a 2D-ACAR spectrometer is set up, with a baseline of 16.5 m, a conventional 22 Na positron source and two Anger-type gamma-cameras. The positrons are guided onto the sample by a magnetic field generated by a normal conducting electromagnet. The sample can be either cooled by a standard closed-cycle-cryostat to low temperatures or heated by a resistive filament to temperatures up to 500 K. We present the key features of this new 2D-ACAR spectrometer and, in addition, discuss first measurements on the pure metal system Cr. The 2D-ACAR measurements have been performed on Cr at different temperatures: at 5 K and at room temperature in the antiferromagnetic phase and at 318 K slightly above the paramagnetic phase transition.

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Positron annihilation and Fermi surface studies: a new approach

Cited by 292 publications

References 20 publications

Calculation of positron states and annihilation in solids: A density-gradient-correction scheme

Calculation of positron states and annihilation in solids: A density-gradient-correction scheme

Direct Observation of the Multisheet Fermi Surface in the Strongly Correlated Transition Metal CompoundZrZn2

First measurements with the Munich 2D-ACAR spectrometer on Cr

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