GWlifetimes of quasiparticle excitations in paramagnetic transition metals

Abstract

We present ab initio calculations of the quasiparticle lifetime in cubic transition metals ͑V, Nb, Ta, Mo, W, Rh, and Ir͒ performed within the GW approximation. By analyzing the behavior of the lifetime as a function of the exciting energy, we demonstrate that upon moving along the d periods and within the d groups of the Periodic table, the changes in d-band width, filling, and shape have a strong effect on quasiparticle lifetimes and result in trends fundamentally distinct from those predicted within the homogeneous electron gas model. We show that ͑E − E F ͒ is mainly determined by the density of d states localized in the vicinity of the Fermi level E F and by the Coulomb interaction screened by d electrons. By making use of this partially screened interaction instead of the fully screened one, we estimate quasiparticle lifetimes in Ir 3 Nb with L1 2 structure and Rh 3 Ir with D0 22 structure.

Inelastic quasiparticle lifetimes of the Shockley surface state band on Ni(111)

“…2 the quasiparticle lifetime data shows an asymmetry with respect to the Fermi energy. Such an electronhole asymmetry has been reported previously for other transition metals [1]. For electron lifetimes, Fermi's golden rule within the random-k approximation can be used [4]:…”

“…Excellent agreement between experiment and theory has been achieved [3,12,19]. Nonetheless for other transition metals, only fundamental tendencies have been investigated theoretically [1], and quasiparticle lifetimes of ferromagnetic elements have been calculated for the bulk only [2,4]. The magnetic exchange splitting and the linewidths of some rare earth elements with a d-like surface state have been investigated with STS [14,20], while on the Ni(111) selfenergy changes of the surface resonance have been measured with two-photon photoemission spectroscopy (2PPES) [21].…”

Experimental time-resolved photoemission andab initiostudy of lifetimes of excited electrons in Mo and Rh

“…At |E − E F | ≈ 3.0 eV, the ratio γ has knolls running up to 1.13 for electrons and 1.17 for holes. Calculations performed with taking into account only d states have corroborated 36 the dominant role of the d-band in formation of the excited electrons dynamics in transition metals.…”

“…36 This means that the d-band plays a dominant role and only 4d states can be treated to quickly assess the imaginary part of the self-energy and the lifetime.…”

Hot electron lifetimes in metals probed by time-resolved two-photon photoemission

“…Advanced theoretical approaches [62,70,122] and TR-2PPE experiments [195] confirm this general trend. More specifically, details such as occupation, width and shape of the d-bands dominantly affect the lifetime and can finally result in a behavior which is fundamentally different from an FLT type behavior [196,197]. The presence of sp-bands is only of minor relevance.…”