Zhao S Y Frank, Poccia Nicola, Panetta Margaret G, Yu Cyndia, Johnson Jedediah W, Yoo Hyobin, Zhong Ruidan, Gu G D, Watanabe Kenji, Taniguchi Takashi, Postolova Svetlana V, Vinokur Valerii M, Kim Philip
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2019 Jun 21;122(24):247001. doi: 10.1103/PhysRevLett.122.247001.
We developed novel techniques to fabricate atomically thin Bi_{2.1}Sr_{1.9}CaCu_{2.0}O_{8+δ} van der Waals heterostructures down to two unit cells while maintaining a transition temperature T_{c} close to the bulk, and carry out magnetotransport measurements on these van der Waals devices. We find a double sign change of the Hall resistance R_{xy} as in the bulk system, spanning both below and above T_{c}. Further, we observe a drastic enlargement of the region of sign reversal in the temperature-magnetic field phase diagram with decreasing thickness of the device. We obtain quantitative agreement between experimental R_{xy}(T,B) and the predictions of the vortex dynamics-based description of Hall effect in high-temperature superconductors both above and below T_{c}.
我们开发了新颖的技术来制备原子级薄的Bi₂.₁Sr₁.₉CaCu₂.₀O₈₊δ范德华异质结构，其厚度低至两个晶胞，同时保持接近体材料的转变温度Tc，并对这些范德华器件进行磁输运测量。我们发现霍尔电阻Rxy如同在体材料系统中一样，在Tc上下都出现双符号变化。此外，我们观察到随着器件厚度减小，温度 - 磁场相图中符号反转区域急剧扩大。我们在实验测得的Rxy(T,B)与基于涡旋动力学的高温超导霍尔效应描述在Tc上下的预测之间获得了定量一致性。
