Magnetic field-induced pair density wave state in the cuprate vortex halo.

Edkins, S D; Kostin, A; Fujita, K; Mackenzie, A P; Eisaki, H; Uchida, S; Sachdev, Subir; Lawler, Michael J et al. · Science · 2019

basic_science · Level V

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Abstract

High magnetic fields suppress cuprate superconductivity to reveal an unusual density wave (DW) state coexisting with unexplained quantum oscillations. Although routinely labeled a charge density wave (CDW), this DW state could actually be an electron-pair density wave (PDW). To search for evidence of a field-induced PDW, we visualized modulations in the density of electronic states <i>N</i>(<i>r</i>) within the halo surrounding Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8</sub> vortex cores. We detected numerous phenomena predicted for a field-induced PDW, including two sets of particle-hole symmetric <i>N</i>(<i>r</i>) modulations with wave vectors <b><i>Q<sub>P</sub></i> </b> and <b>2<i>Q</i> <sub>P</sub></b> , with the latter decaying twice as rapidly from the core as the former. These data imply that the primary field-induced state in underdoped superconducting cuprates is a PDW, with approximately eight CuO<sub>2</sub> unit-cell periodicity and coexisting with its secondary CDWs.