相关论文: Time of life as it is in LiFeAs
Amongst the iron-based superconductors, LiFeAs is unrivalled in the simplicity of its crystal structure and phase diagram. However, our understanding of this canonical compound suffers from conflict between mutually incompatible…
Using a realistic ten-orbital tight-binding model Hamiltonian fitted to the angle-resolved photoemission (ARPES) data on LiFeAs, we analyze the temperature, frequency, and momentum dependencies of quasiparticle interference (QPI) to…
Several models of the strange-metal state of the cuprate superconductors postulate the existence of strong inelastic forward scattering of the electrons, but direct evidence of such scattering is missing. Here, we show that angle-resolved…
Several angle resolved photoemission spectroscopy (ARPES) studies reveal a poorly nested Fermi surface of LiFeAs, far away from a spin density wave instability, and clear-cut superconducting gap anisotropies. On the other hand a very…
The lack of nesting of the electron and hole Fermi-surface sheets in the Fe-based superconductor LiFeAs, with a critical temperature of 18 K, has led to questions as to whether the origin of superconductivity in this material might be…
The existence of coherent quasiparticles near the Fermi energy in the low temperature state of high-temperature superconductors has been well established by angle-resolved photoemission spectroscopy (ARPES). This technique directly probes…
A crucial step in revealing the nature of unconventional superconductivity is to investigate the symmetry of the superconducting order parameter. Scanning tunneling spectroscopy has proven a powerful technique to probe this symmetry by…
We present a calculation of the quasiparticle decay rate due to electron-electron interactions in a doped graphene sheet. In particular, we emphasize subtle differences between the perturbative calculation of this quantity in a doped…
We show that atomic Fermi mixtures with density and mass imbalance exhibit a rich diversity of scaling laws for the quasiparticle decay rate beyond the quadratic energy and temperature dependence of conventional Fermi liquids. For certain…
We study with ARPES the renormalization and quasiparticle lifetimes of the $d_{xy}$ and $d_{xz}$/$d_{yz}$ orbitals in two iron pnictides, LiFeAs and Ba(Fe$_{0.92}$Co$_{0.08}$)$_2$As$_2$ (Co8). We find that both quantities depend on orbital…
We use time-resolved thermometry to monitor the decay of nonequilibrium quasiparticles in superconducting Al in the temperature range from $0.3\,$K to $1.2\,$K. The quasiparticle lifetime at higher temperatures ($T>0.7\,$K) agrees well with…
LiFeAs is unique among the arsenic based Fe-pnictide superconductors because it is the only nearly stoichiometric compound which does not exhibit magnetic order. This is at odds with electronic structure calculations which and a very stable…
Cooper pairing in the iron-based high-Tc superconductors is often conjectured to involve bosonic fluctuations. Among the candidates are antiferromagnetic spin-fluctuations and d-orbital fluctuations amplified by phonons. Any such…
We study the dynamical quasiparticle scattering by spin and charge fluctuations in Fe-based pnictides within a five-orbital model with on-site interactions. The leading contribution to the scattering rate is calculated from the second-order…
When quasiparticles in a BCS superconductor recombine into Cooper pairs, phonons are emitted within a narrow band of energies above the pairing energy at 2$\Delta$. We show that a phonon bandgap restricting the escape of recombination…
Superconducting pnictides are widely found to feature spin-singlet pairing in the vicinity of an antiferromagnetic phase, for which nesting between electron and hole Fermi surfaces is crucial. LiFeAs differs from the other pnictides by (i)…
In this article we review our angle- and time-resolved photoemission studies (ARPES and trARPES) on various ferropnictides.
We consider the lifetime of quasi-particles in a d-wave superconductor due to scattering from antiferromagnetic spin-fluctuations, and explicitly separate the contribution from Umklapp processes which determines the electrical conductivity.…
One of the key challenges in the field of high-temperature superconductivity is understanding the nature of fermionic quasiparticles. Experiments consistently demonstrate the existence of a second energy scale, distinct from the d-wave…
We find that heavy fermion systems can have bulk "Fermi arcs", with the use of the non-Hermitian topological theory. In an interacting electron system, the microscopic many-body Hamiltonian is Hermitian, but the one-body quasiparticle…