Engineering topics

Lee, J. -S.

Publications and source records attributed to Lee, J. -S..

3 records

DOE OSTI2023

Enhanced charge density wave with mobile superconducting vortices in La 1.885 Sr 0.115 CuO 4

Superconductivity in the cuprates is found to be intertwined with charge and spin density waves. Determining the interactions between the different types of order is crucial for understanding these important materials. Here, we elucidate the role of the charge density wave (CDW) in the prototypical cuprate La 1.885 Sr 0.115 CuO 4 , by studying the effects of large magnetic fields (H) up to 24 Tesla. At low temperatures (T), the observed CDW peaks reveal two distinct regions in the material: a majority phase with short-range CDW coexisting with superconductivity, and a minority phase with longer-range CDW coexisting with static spin density wave (SDW). With increasing magnetic field, the CDW first grows smoothly in a manner similar to the SDW. However, at high fields we discover a sudden increase in the CDW amplitude upon entering the vortex-liquid state. Our results signify strong coupling of the CDW to mobile superconducting vortices and link enhanced CDW amplitude with local superconducting pairing across the H -T phase diagram.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2022

Enhanced charge density wave coherence in a light-quenched, high-temperature superconductor

Superconductivity and charge density waves (CDWs) are competitive, yet coexisting, orders in cuprate superconductors. To understand their microscopic interdependence, a probe capable of discerning their interaction on its natural length and time scale is necessary. We use ultrafast resonant soft x-ray scattering to track the transient evolution of CDW correlations in YBa 2 Cu 3 O 6+x after the quench of superconductivity by an infrared laser pulse. We observe a nonthermal response of the CDW order characterized by a near doubling of the correlation length within ≈1 picosecond of the superconducting quench. Our results are consistent with a model in which the interaction between superconductivity and CDWs manifests inhomogeneously through disruption of spatial coherence, with superconductivity playing the dominant role in stabilizing CDW topological defects, such as discommensurations.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2021

Two-Dimensional Superconducting Fluctuations Associated with Charge-Density-Wave Stripes in La 1.87 ⁢Sr 0.13 ⁢Cu 0.99 ⁢Fe 0.01 ⁢O 4

The presence of a small concentration of in-plane Fe dopants in La 1.87 Sr 0.13 Cu 0.99 Fe 0.01 O 4 is known to enhance stripelike spin and charge density wave (SDW and CDW) order and suppress the superconducting T c . Here, we show that it also induces highly two-dimensional superconducting correlations that have been argued to be the signatures of a new form of superconducting order, the so-called pair density wave (PDW) order. In addition, using resonant soft x-ray scattering, we find that the two-dimensional superconducting fluctuation is strongly associated with the CDW stripe. In particular, the PDW signature first appears when the correlation length of the CDW stripe grows over eight times the lattice unit (~8 a). In conclusion, these results provide critical conditions for the formation of the PDW order.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗