From the six-author paper: “In the first region below red-arrow C (near 60 °C), equivalent to region F in the inset of Fig. 5, the resistivity with noise signals can be regarded as zero.” But by “noise signals” they don’t mean measurement noise (and their region C doesn’t look measurement-noise limited, unless their measurement apparatus is orders of magnitude less sensitive than it should be) but rather sample physics—later in that paragraph: “The presence of noise in the zero-resistivity region is often attributed to phonon vibrations at higher temperature.”
The other papers do seem to make that claim, but for example the April paper shows the same data but offset 0.02 Ohm-cm on the y-axis (that is, the April version of the plot [Fig. 6a] goes to zero just below “Tc”, but the six-author arXiv version [Fig. 5] doesn’t). So whatever’s going on there, it doesn’t look like they hooked up their probes and saw only the noise floor of their instrument.
Don’t the authors claim to have measured 0 resistivity (modulo measurement noise)?
From the six-author paper: “In the first region below red-arrow C (near 60 °C),
equivalent to region F in the inset of Fig. 5, the resistivity with noise signals can be regarded as
zero.” But by “noise signals” they don’t mean measurement noise (and their region C doesn’t look measurement-noise limited, unless their measurement apparatus is orders of magnitude less sensitive than it should be) but rather sample physics—later in that paragraph: “The presence of noise in the zero-resistivity region is often attributed to phonon vibrations at higher temperature.”
The other papers do seem to make that claim, but for example the April paper shows the same data but offset 0.02 Ohm-cm on the y-axis (that is, the April version of the plot [Fig. 6a] goes to zero just below “Tc”, but the six-author arXiv version [Fig. 5] doesn’t). So whatever’s going on there, it doesn’t look like they hooked up their probes and saw only the noise floor of their instrument.