Nematic and spin-charge orders driven by hole-doping a charge-transfer insulator

Abstract

Recent experimental discoveries have brought a diverse set of broken symmetry states to the center stage of research on cuprate superconductors. Here, we focus on a thematic understanding of the diverse phenomenology by exploring a strong-coupling mechanism of symmetry breaking driven by frustration of antiferromagnetic (AFM) order. We achieve this through a variational study of a three-band model of the CuO 2 plane with Kondo type exchange couplings between doped oxygen holes and classical copper spins. Two main findings from this strong-coupling multi-band perspective are (1) that the symmetry hierarchy of spin stripe, charge stripe, intra-unit-cell nematic order and isotropic phases are all accessible microscopically within the model, (2) many symmetrybreaking patterns compete with energy differences within a few meV per Cu atom to produce a rich phase diagram. These results indicate that the diverse phenomenology of broken-symmetry states in hole-doped AFM charge-transfer insulators may indeed arise from hole-doped frustration of antiferromagnetism.

Density-wave instabilities of fractionalized Fermi liquids

“…A number of recent theoretical works [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] have tried to approach this problem from a weakcoupling approach, where the CDW is interpreted as an instability of a large Fermi surface in the presence of strong antiferromagnetic (AFM) exchange interactions. There are two fundamental properties associated with a CDW-its wavevector, Q, and its form factor, P Q (k), -where the CDW is expressed in real space as a bond-observable, P ij = c † iα c jα (c iα annihilates an electron on the Cu site i with spin α) given by P ij = Q k P Q (k)e ik·(r i −r j ) e iQ·(r i +r j )/2 .…”

Atomic-scale electronic structure of the cuprate d-symmetry form factor density wave state

“…Such a state is then described by A(r) = D(r) cos(φ(r) + φ 0 (r)), where A(r) represents whatever is the modulating electronic degree of freedom, φ(r) = Q x · r is the DW spatial phase at location r, φ 0 (r) represents disorder related spatial phase shifts, and D(r) is the magnitude of the d-symmetry form factor 14,21,23 . To distinguish between the various microscopic mechanisms proposed for the Q = (Q, 0); (0, Q) dFF-DW state of cuprates [17][18][19][20][21][22][23][24][25][26][27][28][29] , it is essential to establish its atomic-scale phenomenology, including the momentum space (k-space) eigenstates contributing to its spectral weight, the relationship (if any) between modulations occurring above and below the Fermi energy, whether the modulating states in the DW are associated with a characteristic energy gap, and how the dFF-DW evolves with doping.To visualize such phenomena directly as in Fig. 1c, we use sublattice-phase-resolved imaging of the electronic structure 14 of the CuO 2 plane.…”

“…This is relevant to the high-temperature superconducting cuprates because numerous researchers have recently proposed that the 'pseudogap' regime 1,2 (PG in Fig. 1a) contains an unconventional density wave with a d-symmetry form factor [17][18][19][20][21][22][23][24][25][26][27][28][29] . The basic phenomenology of such a state is that intraunit-cell (IUC) symmetry breaking renders the O x and O y sites within each CuO 2 unit-cell electronically inequivalent, and that this inequivalence is then modulated periodically at wavevector Q parallel to (1,0);(0,1).…”

Doping asymmetry and striping in a three-orbitalCuO2Hubbard model

“…One-band Hubbard and t-J models have been found, within various approximations, to exhibit striped charge and spin structures [19][20][21][22][23][24] , modulated nematic phases [25][26][27] as well as pair density wave phases [28][29][30] . RPA calculations for the three-band Hubbard model have also found nematic phases in certain parameter regimes [31][32][33] .…”