Charge Density Wave Memory in a Cuprate Superconductor

Researchers revealed a new puzzle piece that could affect how we currently understand superconductivity

crystal configurations and measured CDW speckle patterns enlarge

Different crystal configurations (top) and measured CDW speckle patterns (left) at different temperatures. The graphic illustrates how the patterns change once the cycling crosses above TLTO.

The Science         

Scientists revealed that the charge density wave (CDW) stripe domains in the high-temperature superconductor (HTSC) La1.875Ba0.125CuO4 display a memory effect where the same domain configuration is reproduced after cycling above the CDW transition temperature.

The Impact

This work showed that the charge order is fixed by pinning centers that set in at much higher temperatures. This provides an additional constraint on theories of superconductivity in these materials.

Summary

Scientists revealed that the pinning of CDW stripe domains only changes on warming above the tetragonal transition temperature (TLTT) at 240 K. A CDW is an ordered quantum fluid of electrons, which usually forms "standing wave" patterns to carry the electric current through materials.

In this study, the team of scientists investigated La1.875Ba0.125CuO4 (LBCO 1/8), a high-temperature superconductor that is known to form CDWs. The team used coherent resonant x-ray speckle correlation analysis to directly determine the reproducibility of CDW domain patterns in the material during thermal cycling. They performed the measurements at the Coherent Soft X-ray Scattering (CSX) beamline at the National Synchrotron Light Source II (NSLS-II), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE’s Brookhaven National Laboratory.

While the CDW order is only observed below 54 K, the scientists discovered remarkably reproducible CDW domain memory upon repeated cycling to far higher temperatures. They found that the memory is only lost on cycling to 240 K, when the material changes its crystal structure from tetragonal to orthorhombic. The scientists inferred that these structural features that develop below 240 K determine the CDW pinning landscape below 54 K.

This opens a new view into the complex coupling between charge and lattice degrees of freedom in superconducting cuprates.

Download the research summary slide (PDF)

Related Links

Feature Story: "A Superconductor That "Remembers" its Electronic Charge Arrangement"

Contact

Xiaoqian M. Chen
Lawrence Berkeley National Laboratory
xmchen@lbl.gov

Mark P.M. Dean
Brookhaven National Laboratory
mdean@bnl.gov

 Stuart B. Wilkins
Brookhaven National Laboratory
swilkins@bnl.gov

Ian K. Robinson
Brookhaven National Laboratory
irobinson@bnl.gov

Publications

X. M. Chen, C. Mazzoli, Y. Cao, V. Thampy, A. M. Barbour, W. Hu, M. Lu, T. A. Assefa, H. Miao, G. Fabbris, G. D. Gu, J. M. Tranquada, M. P. M. Dean, S. B. Wilkins & I. K. Robinson , “Charge density wave memory in a cuprate superconductor”, Nat. Comms. 10:1435 1-6 (2019). DOI: 10.1038/s41467-019-09433-1

Funding

The work at Brookhaven National Laboratory was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract no. DESC0012704. This research used resources the Coherent Soft X-ray Scattering (CSX) beamline 23-ID-1 of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract no. DE-SC0012704. The sample pattern was performed at the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704. Work at Argonne National Laboratory was supported by the US Department of Energy, Office of Basic Energy Sciences, under Contract no. DE-AC0206CH11357.

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