Quantitative measurement of the spectral function of aluminum and lithium by electron momentum spectroscopy

Abstract

We present measurements of the spectral function of aluminum and lithium using high-energy electron momentum spectroscopy. For aluminum the quasiparticle peaks show clear asymmetries and significant satellite intensity that extends over a wide region to larger binding energies. The intensity distribution is not well described by band structure calculations. These data are described only by calculations based on the manybody cumulant expansion scheme. The measured momentum distribution at the Fermi level agrees with the theoretical one within 0.03 a.u. For lithium a bandwidth of 3.0 eV is obtained.

EMS Measurement of the Valence Spectral Function of Silicon – A Test of Many‐body Theory

“…The latter is also quite asymmetric. As well as the raw data the figure includes a curve showing the data deconvoluted, in a parameterfree way, for inelastic scattering using only the measured energy loss spectrum (see Fig.1.2) [1]. This still leaves considerable intensity at high binding energies, extending some 20 eV or more above the position of the quasiparticle peak.…”

“…The experimental energy and momentum resolutions were discussed in detail by Vos et al [1]. The full width at half-maximum (FWHM) energy resolution is 1.0 eV, whereas the FWHM momentum resolutions are estimated to be (0.12, 0.10, 0.10 a.u.)…”

“…This density is due to the 111 reciprocal lattice vector (the shortest reciprocal lattice vector for the diamond lattice, length 1.06 a.u.) shifting density from Γ (1,1,1) to Γ (1,0,0) . Rotation by 10…”

“…Presuming that the Green's function can be diagonalized on an appropriate basis of momentum-space quasiparticle states φ j (q) (e.g. orbitals in atoms, Bloch waves in crystals) then for a crystal it takes the form [1] A(q, ω) = j,k,G |φ j (q)| 2 δ q,(k+G)…”

“…In addition electron correlation effects can give rise to significant satellite structures. The full SEMD can be measured by electron momentum spectroscopy (EMS) [1,2], in which the energies E 0 , E 1 and E 2 and momenta k 0 , k 1 and k 2 of the incident (subscript 0) and two outgoing electrons (subscripts 1 and 2) in high-energy high-momentum-transfer (e, 2e) ionizing collisions are fully determined. From energy and momentum conservation one can determine for each (e, 2e) event the binding (or separation) energy of the ejected electron 4) and the recoil momentum of the ionized specimen…”