In underdoped cuprates, an incommensurate charge density wave (CDW) order is known to coexist with superconductivity. A dip in $T_c$ at the hole doping level where the CDW is strongest ($n_p\simeq 0.12$) suggests that CDW order may suppress superconductivity. We investigate the interplay of charge order with superconductivity in underdoped ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ by measuring the temperature dependence of the Hall coefficient $R_H(T)$ at high magnetic field and at high hydrostatic pressure. We find that, although pressure increases $T_c$ by up to 10 K at 2.6 GPa, it has very little effect on $R_H(T)$. This suggests that pressure, at these levels, only weakly affects the CDW and that the increase in $T_c$ with pressure cannot be attributed to a suppression of the CDW. We argue, therefore, that the dip in $T_c$ at $n_p\simeq 0.12$ at ambient pressure is probably not caused by the CDW formation.

中文翻译：

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负压下YBa2Cu3O7-δ掺杂的电荷序和超导

在掺杂不足的铜酸盐中，已知不相称的电荷密度波（CDW）与超导共存。浸入${Ť}_C$ 在CDW最强的空穴掺杂水平（${ñ}_p\simeq 0.12$）表明CDW阶可能会抑制超导性。我们研究了低掺杂中电荷序与超导的相互作用${\mathrm{Ba}}_{\mathrm{2个}}{铜}_3{\mathrm{Ø}}_{7-\delta }$ 通过测量霍尔系数的温度依赖性 ${\mathrm{[R}}_H（Ť）$在高磁场和高静水压力下。我们发现，尽管压力增加${Ť}_C$ 在2.6 GPa时高达10 K ${\mathrm{[R}}_H（Ť）$。这表明在这些水平上的压力只会对CDW产生微弱的影响，而CDW的增加${Ť}_C$压力不能归因于CDW的抑制。因此，我们认为${Ť}_C$ 在 ${ñ}_p\simeq 0.12$ 在环境压力下可能不是由CDW形成引起的。