Related papers: Superconductivity-induced spectral weight transfer…
Quantum geometry quantifies how the electron wavefunction evolves distinctly from conventional transport theory. In noncentrosymmetric materials, nonreciprocal transport with quantum geometric origin remains prominent with localized charge…
In scanning tunneling microscopy (STM) conductance curves, the superconducting gap of cuprates is sometimes accompanied by small sub-gap structures at very low energy. This was documented early on near vortex cores and later at zero…
Both families of high $T_c$ superconductors, iron pnictides and cuprates, exhibit material dependence of superconductivity. Here, we study its origin within the spin fluctuation pairing theory based on multiorbital models that take into…
The carriers in the high-Tc cuprates are found to be polaron-like "stripons" carrying charge and located in stripe-like inhomogeneities, "quasi-electrons" carrying charge and spin, and "svivons" carrying spin and some lattice distortion.…
In band insulators, where the Fermi surface is absent, adiabatic transport is allowed only due to the geometry of the Hilbert space. By driving the system at a small but finite frequency $\omega$, transport is still expected to depend…
A two-band model with repulsive interband coupling and interband {\it transport} (potential) scattering is considered to elucidate their effects on material properties. In agreement with previous work, we find that the bands order…
Optically driven quantum materials exhibit a variety of non-equilibrium functional phenomena [1-11], which are potentially associated with unique transport properties. However, these transient electrical responses have remained largely…
In a flat band superconductor, the charge carriers' group velocity vF is extremely slow, quenching their kinetic energy. The emergence of superconductivity thus appears paradoxical, as conventional BCS theory implies a vanishing coherence…
In cuprate superconductors, tunneling between planes makes possible three-dimensional coherent transport. However, the interlayer tunnelling amplitude is reduced when an order-parameter phase gradient between planes is established. As such,…
Recent experiments indicate that the excitation spectrum of the cuprates is characterised, in the superconducting state, by two energy scales: the ``coherence energy'' \Delta_c and the ``pseudogap'' \Delta_p. Here we consider a simple…
Among the variety of correlated states exhibited by twisted bilayer graphene, cascades in the spectroscopic properties and in the electronic compressibility occur over larger ranges of energy, twist angle and temperature compared to other…
The exotic physics in condensed matter systems, such as high-Tc superconductivity in cuprates, is due to the properties of the elementary excitations and their interactions. The dispersion of the electronic states revealed by angle-resolved…
The theory of hole superconductivity explains high temperature superconductivity in cuprates as driven by pairing of hole carriers in oxygen $p\pi$ orbitals in the highly negatively charged $Cu-O$ planes. The pairing mechanism is hole…
In view of the many quantum field theoretical descriptions of graphene in $2+1$ dimensions, we present another field theoretical feature of graphene, in the presence of defects. Particularly, we shall be interested in gapped graphene in the…
Quantum materials are defined by the emergence of new properties resulting from collective quantum effects and by holding promise for their quantum applications. Novel superconductors, from high-Tc cuprates and iron-based superconductors to…
We have studied the quantum transport in a narrow constriction acted upon by a finite-range longitudinally polarized time-dependent electric field. The electric field induces coherent inelastic scatterings which involve both intra-subband…
High pressure serves as a path finding tool towards novel structures, including those with very high Tc.The superconductivity in sulfur hydrides with record value (203 K) is caused by the phonon mechanism. However, the picture differs from…
A unified theory is outlined for the cuprates, Fe-based, and related superconductors. Their low-energy excitations are approached in terms of auxiliary particles representing combinations of atomic-like electron configurations, and the…
We propose that when the Fermi level lies within a wide band and also lies close to but not within a coexisting narrow band, high $T_c$ superconductivity may take place due to the large number of interband pair scattering channels and the…
By employing x-ray photoelectron spectroscopy (XPS), we have been able to establish the occurrence of charge-transfer doping in few-layer graphene covered with electron acceptor (TCNE) and donor (TTF) molecules. We have performed…