Fluctuating charge-density waves in a cuprate superconductor
Author(s)Torchinsky, Darius H.; Mahmood, Fahad; Bollinger, Anthony T.; Bozovic, Ivan; Gedik, Nuh
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Cuprate materials hosting high-temperature superconductivity (HTS) also exhibit various forms of charge and spin ordering1, 2, 3, 4, 5, 6 whose significance is not fully understood7. So far, static charge-density waves8 (CDWs) have been detected by diffraction probes only at particular doping levels9, 10, 11 or in an applied external field12 . However, dynamic CDWs may also be present more broadly and their detection, characterization and relationship with HTS remain open problems. Here we present a method based on ultrafast spectroscopy to detect the presence and measure the lifetimes of CDW fluctuations in cuprates. In an underdoped La[subscript 1.9]Sr[subscript 0.1]CuO4 film (T[subscript c] = 26 K), we observe collective excitations of CDW that persist up to 100 K. This dynamic CDW fluctuates with a characteristic lifetime of 2 ps at T = 5 K that decreases to 0.5 ps at T = 100 K. In contrast, in an optimally doped La[subscript 1.84]Sr[subscript 0.16]CuO[subscript ]4 film (T[subscript c] = 38.5 K), we detect no signatures of fluctuating CDWs at any temperature, favouring the competition scenario. This work forges a path for studying fluctuating order parameters in various superconductors and other materials.
DepartmentMassachusetts Institute of Technology. Department of Physics
Nature Publishing Group
Torchinsky, Darius H., Fahad Mahmood, Anthony T. Bollinger, Ivan Bozovic, and Nuh Gedik. “Fluctuating Charge-Density Waves in a Cuprate Superconductor.” Nature Materials 12, no. 5 (February 24, 2013): 387–391.
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