相关论文: Non-Fermi Liquid due to Orbital Fluctuations in Ir…
We analyze quantum fluctuation effects at the onset of charge or spin density wave order with a $2k_F$ wave vector $\mathbf{Q}$ in two-dimensional metals -- for the special case where $\mathbf{Q}$ connects a pair of hot spots situated at…
The multi-orbital Hubbard model is investigated in order to clarify the electron correlation effects and the superconductivity in the iron-based superconductor. The renormalization effects on the self-energy and the two-particle irreducible…
When a second-order magnetic phase transition is tuned to zero temperature by a non-thermal parameter, quantum fluctuations are critically enhanced, often leading to the emergence of unconventional superconductivity. In these `quantum…
Recent spectroscopic measurements in a number of strongly correlated metals that exhibit non-Fermi liquid like properties have observed evidence of anomalous frequency and momentum-dependent charge-density fluctuations. Specifically, in the…
Magnetic fluctuations and electrons couple in intriguing ways in the vicinity of zero temperature phase transitions - quantum critical points - in conducting materials. Quantum criticality is implicated in non-Fermi liquid behavior of…
Insight into the electronic structure of the pnictide family of superconductors is obtained from quantum oscillation measurements. Here we review experimental quantum oscillation data that reveal a transformation from large quasi-two…
Recent experiments suggest that besides of antiferromagnetic fluctuations nematic fluctuations may contribute to the occurrence of superconductivity in iron pnictides. Motivated by this observation we study superconductivity from nematic…
We propose a model for the non-Fermi behavior in the proximity of the quantum phase transition induced by the strong polarization of the electrons due to local magnetic moments. The self - consistent Renormalization - Group methods have…
We study the five-orbital Hubbard model including the charge quadrupole interaction for iron pnictides. Using the fluctuation-exchange (FLEX) approximation, orbital fluctuations evolve inversely proportional to the temperature, and…
The electronic states and superconductivity in iron pnictides are studied on the basis of the 16 band $d$-$p$ model which includes both the onsite Coulomb interaction between Fe $d$ electrons and the intersite one between Fe $d$ and…
We study the five-orbital Hubbard-Holstein model for iron pnictides with small electron-phonon interaction due to Fe-ion Einstein oscillators. Using the fluctuation-exchange (FLEX) approximation, orbital fluctuations evolve inversely…
Quantum-mechanical fluctuations between competing phases at $T=0$ induce exotic finite-temperature collective excitations that are not described by the standard Landau Fermi liquid framework. These excitations exhibit anomalous temperature…
With particular reference to the role of the renormalization group approach and Ward identities, we start by recalling some old features of the one-dimensional Luttinger liquid as the prototype of non-Fermi-liquid behavior. Its dimensional…
The signature for a non-Fermi liquid behavior near a quantum phase transition has been observed in thermal and transport properties of many metallic systems at low temperatures. In the present work we consider specific examples of itinerant…
Using determinantal quantum Monte Carlo, we compute the properties of a lattice model with spin $\frac 1 2$ itinerant electrons tuned through a quantum phase transition to an Ising nematic phase. The nematic fluctuations induce…
At the nematic quantum critical point that exists in the $d_{x^2-y^2}$-wave superconducting dome of cuprates, the massless nodal fermions interact strongly with the quantum critical fluctuation of nematic order. We study this problem by…
The nematic electronic state and its associated nematic critical fluctuations have emerged as potential candidates for superconducting pairing in various unconventional superconductors. However, in most materials their coexistence with…
In multi-band metals quasi-particles arising from different atomic orbitals coexist at a common Fermi surface. Superconductivity in these materials may appear due to interactions within a band (intra-band) or among the distinct metallic…
The multiband nature of iron pnictides gives rise to a rich temperature-doping phase diagram of competing orders and a plethora of collective phenomena. At low dopings, the tetragonal-to-orthorhombic structural transition is closely…
A model of copper-oxygen bonding and anti-bonding bands with the most general two-body interactions allowable by symmetry is considered. The model has a continuous transition as a function of hole-density x and temperature T to a phase in…