arXiv subjects

Sangwoo S. Chung

Publications and source records attributed to Sangwoo S. Chung.

6 recordsLinked to original sources

arXiv2023

Superconducting stripes in the hole-doped three-band Hubbard model

We study the ground state properties of the hole-doped three-band Hubbard (Emery) model, describing the copper-oxygen planes of the cuprates, using large-scale 2D tensor network calculations. Our simulations reveal a period 4 stripe state with spin and weak charge order over an extended doping range beyond $δ\sim0.12$ and stripes with larger periods at smaller doping. The period 4 stripe exhibits coexisting $d$-wave superconductivity in the doping range $0.15 \lesssim δ< 0.25$, while at smaller doping around $δ\sim 1/8$ we find a strong competition between superconducting and non-superconducting stripes, including also pair density-wave states with alternating sign structure on neighboring stripes, suggesting that the fate of superconductivity around 1/8 doping may be sensitive on the model parameters.

cond-mat.str-el↗

arXiv2019

Period 4 stripe in the extended two-dimensional Hubbard model

We study the competition between stripe states with different periods and a uniform $d$-wave superconducting state in the extended 2D Hubbard model at 1/8 hole doping using infinite projected entangled-pair states (iPEPS). With increasing strength of negative next-nearest neighbor hopping $t'$, the preferred period of the stripe decreases. For the values of $t'$ predicted for cuprate high-T$_c$ superconductors, we find stripes with a period 4 in the charge order, in agreement with experiments. Superconductivity in the period 4 stripe is suppressed at $1/8$ doping. Only at larger doping, $0.18 \lesssim δ< 0.25$, the period 4 stripe exhibits coexisting $d$-wave superconducting order. The uniform $d$-wave state is only favored for sufficiently large positive $t'$.

cond-mat.str-el↗

arXiv2019

SU(3) Fermions on the Honeycomb Lattice at 1/3-Filling

SU(N) symmetric fermions on a lattice, which can be realized in ultracold-atom-based quantum simulators, have very promising prospects for realizing exotic states of matter. Here we present the ground state phase diagram of the repulsive SU(3) Hubbard model on a honeycomb lattice at 1/3 filling obtained from infinite projected entangled pair states tensor network calculations. In the strongly interacting limit the ground state has plaquette order. Upon decreasing the interaction strength $U/t$ we find a first order transition at $U/t=7.2(2)$ into a dimerized, color-ordered state, which extends down to $U/t=4.5(5)$ at which the Mott transition occurs and the ground state becomes uniform. Our results may serve as a prediction and benchmark for future quantum simulators of SU(3) fermions.

cond-mat.str-el↗

arXiv2017

Multiple phase separation in one-dimensional mixtures of mass- and population-imbalanced attractive Fermi gases

We study the attractive Fermi mixture of a ${}^{6}\mathrm{Li}$-${}^{40}\mathrm{K}$ gas in one dimension using the continuous matrix product states variational ansatz and obtain the $T=0$ phase diagram. We predict an axial density profile that contains four distinct phases trapped induced along one-dimensional (1D) tubes, which is more intricate than those observed in 1D mass-balanced systems or in higher-dimensional gas clouds. The parameter regimes explored are realistic in view of possible future experiments. This an application of continuous matrix product states to a nonintegrable fermionic system.

cond-mat.quant-gas↗

arXiv2015

Matrix product ansatz for Fermi fields in one dimension

We present an implementation of a continuous matrix product state for two-component fermions in one-dimension. We propose a construction of variational matrices with an efficient parameterization that respects the translational symmetry of the problem (without being overly constraining) and readily meets the regularity conditions that arise from removing the ultraviolet divergences in the kinetic energy. We test the validity of our approach on an interacting spin-1/2 system and observe that the ansatz correctly predicts the ground state magnetic properties for the attractive spin-1/2 Fermi gas, including the phase-oscillating pair correlation function in the partially polarized regime.

cond-mat.str-el↗

arXiv2012

Numerical Simulation of the Nernst Effect in Extreme Type-II Superconductors: A Negative Nernst Signal and its Noise Power Spectra

Recently, different transport coefficients have been measured in High-Tc superconductors to pinpoint the nature of the pseudogap phase. In particular, the thermoelectric coefficients received a considerable attention both theoretically and experimentally. We numerically simulate the Nernst effect in extreme type-II superconductors using the time-dependent Ginzburg-Landau equations. We report the sign reversal of the thermoelectric coefficient, alpha_xy, at temperatures close to the mean-field transition temperature, Tc^{MF}(H), which qualitatively agrees with recent experiments on high-Tc materials. We also discuss the noise power spectrum of alpha_xy, which shows 1/f^beta behavior. Based on this observation, we propose an experiment to distinguish among different regimes of vortex dynamics by measuring the noise correlations of the Nernst signal.

cond-mat.supr-con↗