MAGNETOTRANSPORT SIGNATURES OF ANTIFERROMAGNETISM COEXISTING WITH CHARGE ORDER IN A HIGH-T_C SUPERCONDUCTOR

Vincent Oliviero, David Vignolles, Cyril Proust, LNCMI Toulouse.

In the last few years, high-magnetic-field studies have allowed great breakthroughs in the understanding of the physics of high-T_c cuprate superconductors. Here, we report the measurements of quantum oscillations and Hall effect in high magnetic fields up to 88 T in the underdoped trilayered cuprate HgBa₂Ca₂Cu₃O_8+δ (Hg1223). Multilayered cuprates possess not only the highest T_c but also offer a unique platform to study disorder-free CuO₂ planes and the interplay between competing orders with superconductivity.
Figure 1 shows the variation of the tunnel diode oscillator (TDO) circuit frequency as a function of magnetic field at doping level p = 8 % (symbols) where clear quantum oscillations are visible. The inset shows the Fourier analysis of the oscillatory part of the data at 1.4 K, showing that we can isolate at least three quantum-oscillation frequencies at F₁≈350 T, F₂≈500 T, and F₃≈850 T, where F₁≈F₃ − F₂. Solid lines in the main figure are the simultaneous fits in the temperature range between 1.4 and 4.2K using the Lifshitz-Kosevich theory, that confirm the accurate determination of the frequencies. The presence of three frequencies is explained by a scenario where an antiferromagnetic (AFM) order is present in the inner plane coexisting with a charge order in the outer plane (see Fig. 2a) resulting in the Fermi-surface reconstruction depicted in Fig. 2b. In that scenario, F₃ and F₂ correspond to electron (orange) and hole (purple) pockets, respectively. The third frequency F₁≈F₃ − F₂ would correspond to magnetic breakdown tunnelling between inner and outer planes. Our interpretation implies that, in the cuprate where T_c is maximum among all superconductors, a metallic AFM state extends deep into the superconducting phase. This is reminiscent of a quantum critical point scenario observed in other unconventional superconductors, where spin fluctuations extend away from the AFM ordered state. All of the above considerations strongly suggest a magnetic pairing mechanism for cuprates. In Hg1223, the clean nature and the absence of buckling of the inner CuO₂ plane support the idea that the antiferromagnetic interaction J is large, leading to higher T_c.

Figure 1: Field dependence of the TDO frequency in Hg1223 (p = 8 %) at different temperatures (symbols). Solid lines correspond to the fits to the data using the Lifshitz-Kosevich theory plus a polynomial background in the field range 40 ≤ H ≤ 83 T. The inset shows the Fourier analysis of the oscillatory part of the data measured at 1.4 K along with the contribution of F₁ (blue), F₂ (grey), and F₃ (red).

Figure 2: a) Crystallographic structure of trilayer Hg1223. We sketch the presence of AFM order in the inner plane (purple arrow) and charge order (orange wave) in the outer planes. b) Corresponding reconstructed Fermi surface in presence of AFM order in the inner plane leading to a hole pocket (purple, F₂) and charge order in the outer plane leading to an electron pocket (orange, F₃).

Magnetotransport signatures of antiferromagnetism coexisting with charge order in the trilayer cuprate HgBa₂Ca₂Cu₃O_8+δ, V. Oliviero, S. Benhabib, I. Gilmutdinov, B. Vignolle, L. Drigo, M. Massoudzadegan, M. Leroux, G. L. J. A. Rikken, A. Forget, D. Colson, D. Vignolles, and C. Proust, Nat. Commun. 13, 1568 (2022)

https://www.nature.com/articles/s41467-022-29134-6

Contact: cyril.proust@lncmi.cnrs.fr, david.vignolles@lncmi.cnrs.fr