Division of Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
Division of Physics and Applied Physics, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore and Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.
Phys Rev Lett. 2014 Jan 17;112(2):026101. doi: 10.1103/PhysRevLett.112.026101. Epub 2014 Jan 14.
We investigate the behavior of electric fields originating from adsorbates deposited on a cryogenic atom chip as it is cooled from room temperature to cryogenic temperature. Using Rydberg electromagnetically induced transparency, we measure the field strength versus distance from a 1 mm square of yttrium barium copper oxide (YBCO) patterned onto a yttria stabilized zirconia chip substrate. We find a localized and stable dipole field at room temperature and attribute it to a saturated layer of chemically adsorbed rubidium atoms on the YBCO. As the chip is cooled towards 83 K we observe a change in sign of the electric field as well as a transition from a localized to a delocalized dipole density. We relate these changes to the onset of physisorption on the chip surface when the van der Waals attraction overcomes the thermal desorption mechanisms. Our findings suggest that through careful selection of substrate materials, it may be possible to reduce the electric fields caused by atomic adsorption on chips, opening up experiments to controlled Rydberg-surface coupling schemes.
我们研究了在低温原子芯片上冷却时，由吸附在其上的吸附物产生的电场的行为。我们使用里德堡电磁感应透明技术，测量了一个 1 毫米见方的钇钡铜氧化物 (YBCO) 图案在氧化钇稳定氧化锆芯片基底上的距离与场强的关系。我们在室温下发现了一个局部且稳定的偶极场，并将其归因于 YBCO 上化学吸附的饱和铷原子层。当芯片冷却到 83 K 时，我们观察到电场的符号发生了变化，并且偶极密度从局部化转变为非局域化。我们将这些变化与芯片表面物理吸附的开始联系起来，当范德华吸引力克服热脱附机制时，就会发生这种情况。我们的研究结果表明，通过仔细选择衬底材料，有可能减少芯片上原子吸附引起的电场，从而为受控里德堡-表面耦合方案的实验打开了大门。
