Carrier dynamics in doped bilayer iridates near magnetic quantum criticality

Abstract

Motivated by experiments on the carrier-doped bilayer iridate (Sr1−xLax)3Ir2O7, we study the dynamics of a single doped electron in a bilayer magnet in the presence of spin-orbit coupling, taking into account the spatially staggered rotation of IrO6 octahedra. We employ an effective singleorbital bilayer t-J model, concentrating on the quantum paramagnetic phase near the magnetic quantum critical point. We determine the carrier dispersion using a combination of self-consistent Born and bond-operator techniques. Extrapolating to finite small carrier density we find that, for experimentally relevant parameters, the combination of octahedral rotation and spin-orbit coupling induces a band folding which results in a Fermi surface of small double electron pockets, in striking agreement with experimental observations. We also determine the influence of spin-orbit coupling on the location of the quantum critical point in the undoped case, and discuss aspects of the global phase diagram of doped bilayer Mott insulators. arXiv:1803.08516v3 [cond-mat.str-el]

Quasiparticle Band Structure and Spin Excitation Spectrum of the Kondo Lattice

“…It is the purpose of the present manuscript to present a theory for the single-particle band structure and spin excitation spectrum of the Kondo lattice which relies on the interpretation of the eigenstates of a single cell as fermionic or bosonic particles, which we call bond particles. Bond particle theory was proposed originally by Sachdev and Bhatt [72] to study spin systems and applied to spin ladders [73], bilayers [74,75], intrisically dimerized spin systems [76,77] and the 'Kondo necklace' [78]. It was also applied to the PAM [79], as well as antiferromagnetic (AF) ordering in the planar KLM [80,81], a discussion of its different AF phases [82] and the band structure in the AF phase [83].…”

Bond particle theory for the pseudogap phase of underdoped cuprates

“…More precisely, in the following we apply bond particle theory to the t-J model. This was proposed by Sachdev and Bhatt 46 and applied subsequently to spin ladders [63][64][65] , bilayers 66,67 , intrisically dimerized spin systems 68,69 and the 'Kondo necklace' 70 .…”