Related papers: Doping a semiconductor to create an unconventional…
We model the underdoped cuprates using fermions moving in a background with local antiferromagnetic order. The antiferromagnetic order fluctuates in orientation, but not in magnitude, so that there is no long-range antiferromagnetism, but a…
In spatial dimensions d >= 2, Kondo lattice models of conduction and local moment electrons can exhibit a fractionalized, non-magnetic state (FL*) with a Fermi surface of sharp electron-like quasiparticles, enclosing a volume quantized by…
An intense investigation of possible non-Fermi liquid states of matter has been inspired by two of the most intriguing phenomena discovered in the past quarter century, namely high temperature superconductivity and the fractional quantum…
The Kondo effect in a Tomonaga-Luttinger liquid ($U<<t$) is studied by using the non-Abelian bosonization. The $q=2k_F$ enhanced spin fluctuations generate a special Kondo effect, for any sign of the exchange coupling $J_K$…
We address Coulomb drag and near-field heat transfer in a double-layer system of incoherent metals. Each layer is modeled by an array of tunnel-coupled SYK dots with random inter-layer interactions. Depending on the strength of intra-dot…
We characterize the electron doping evolution of (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$ by means of angle-resolved photoemission. Concomitant with the metal insulator transition around $x\approx0.05$ we find the emergence of coherent…
When a magnetic moment is embedded in a metal, it captures itinerant electrons to form the Kondo cloud1,2, which can spread out over a few micrometres3,4. For a metal with dense magnetic impurities such that Kondo clouds overlap with each…
Experiments show that at even denominator fractions (EDFs) ($\nu=1/2, 3/4, 3/2$,...) the two-dimensional electron gas in a strong magnetic field becomes compressible, has no energy gap, and demonstrates the presence of an ostensible Fermi…
I review recent work on magnetic dynamics of the high temperature superconductors using a model that combines two weakly interacting species of low-energy excitations: the antiferromagnetic spin waves which carry spin-1 and no charge, and…
Doping a Mott-insulating $\mathbb{Z}_2$ spin liquid can lead to a fractionalized Fermi liquid (FL*). Such a phase has several favorable features that make it a candidate for the pseudogap metal for the underdoped cuprates. We focus on a…
We obtain the conditions necessary for the emergence of various low temperature ordered states (local moment antiferromagnetism, unconventional superconductivity, quantum criticality, and Landau Fermi liquid behavior) in Kondo lattice…
Non-Fermi liquid behavior of strongly correlated Fermi systems is derived within the Landau approach. We attribute this behavior to a phase transition associated with a rearrangement of the Landau state that leads to flattening of a portion…
The interplay of interactions and disorder in two-dimensional (2D) electron systems has actively been studied for decades. The paradigmatic approach involves starting with a clean Fermi liquid and perturbing the system with both disorder…
We use magnetic quantum oscillations in the underdoped high Tc superconductor YBa_2Cu_3O_(6+x) (x=0.56) measured over a broad range of temperatures 100 mK<T<18 K to extract the form of the distribution function describing the low-lying…
We show that doped Mott insulators exhibit a collective degree of freedom, not made out of the elemental excitations, because the number of single-particle addition states at low energy per electron per spin is greater than one. The…
Entanglement of spin and orbital Kondo effect is investigated on the basis of a Kondo-type exchange model with twofold orbital degeneracy. By using Wilson's numerical renormalization-group method, we examine dynamical and thermal properties…
A long standing mystery of fundamental importance in correlated electron physics is to understand strange non-Fermi liquid metals that are seen in diverse quantum materials. A striking experimental feature of these metals is a resistivity…
To identify what types of non-Fermi liquid (NFL) behavior are most likely to occur in cubic metals due to doublet impurities, we derive every cubic symmetry-allowed, NFL, Kondo-type exchange coupling that does not need accidental degeneracy…
The interplay of Kondo screening and magnetic ordering in strongly correlated materials containing local moments is a subtle problem.[1] Usually the number of conduction electrons matches or exceeds the number of moments, and a…
Systematic deviations from standard Fermi-liquid behavior have been widely observed and documented in several classes of strongly correlated metals. For many of these systems, mounting evidence is emerging that the anomalous behavior is…