发表机构
Stanford University（斯坦福大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究制备出3.6吉赫兹下内部声子寿命达21毫秒的铌酸锂声子晶体谐振器，证实其寿命由外部耦合而非材料损耗决定，确立了铌酸锂兼具高本征品质与强机电耦合的特性。
AI 中文摘要
工作在吉赫兹频率的压电纳米机械谐振器是量子信息处理和精密传感的有前景平台，但声子寿命此前被限制在微秒范围，这一现象被广泛归因于压电材料的较高本征损耗。本研究表明该限制并非根本性的：利用近期对铌酸锂缺陷介导损耗研究得到的制备工艺，结合离子铣削表面的化学修复与阴影掩模金属化工艺，制备出的铌酸锂声子晶体谐振器在3.6吉赫兹下推断出的内部声子寿命可达21毫秒，对应毫开尔文温度下品质因数超过$4\times10^8$（$f \times Q_i > 10^{18}$）。通过系统改变电极与谐振器的间距，研究证实测得的寿命由器件与测量电路间的外部耦合决定，而非材料损耗。这表明铌酸锂在去除制备诱导的表面损伤后，可达到与最优机械材料相当的本征品质，同时仍保持强机电耦合的本征压电平台特性。
英文摘要
Piezoelectric nanomechanical resonators operating at gigahertz frequencies are a promising platform for quantum information processing and precision sensing, but phonon lifetimes have been limited to the microsecond range, widely attributed to the higher intrinsic loss of piezoelectric materials. Here we show that this limitation is not fundamental. Using a fabrication process informed by recent studies of defect-mediated loss in lithium niobate, we combine chemical restoration of ion-milled surfaces with a shadow-mask metallization process to produce lithium niobate phononic crystal resonators with inferred internal phonon lifetimes of up to 21 milliseconds at 3.6 gigahertz, corresponding to quality factors exceeding $4\times10^8$ ($f\cdot Q_i > 10^{18}$) at millikelvin temperatures. By systematically varying the electrode-to-resonator spacing, we demonstrate that the measured lifetime is set by external coupling between the device and the measurement circuit rather than material loss. This establishes that lithium niobate, once fabrication-induced surface damage is removed, achieves an intrinsic quality comparable to the best mechanical materials while remaining an intrinsically piezoelectric platform with strong electromechanical coupling.
Comments17 pages, 3 main figures, 8 appendix figures
