Uniaxial stress effect on quasi-one-dimensional Kondo lattice CeCo2Ga8

Quantum critical phenomena in the quasi-one-dimensional limit remain an open issue. We report the uniaxial stress effect on the quasi-one-dimensional Kondo lattice CeCo$_2$Ga$_8$ by electric transport and AC heat capacity measurements. CeCo$_2$Ga$_8$ is speculated to sit in close vicinity but on the quantum-disordered side of a quantum critical point. Upon compressing the ${c}$ axis, parallel to the Ce-Ce chain, the onset of coherent Kondo effect is enhanced. In contrast, the electronic specific heat diverges more rapidly at low temperature when the intra-chain distance is elongated by compressions along ${a}$ or ${b}$ axis. These results suggest that a tensile intra-chain strain ($\varepsilon_c >0$) pushes CeCo$_2$Ga$_8$ closer to the quantum critical point, while a compressive intra-chain strain ($\varepsilon_c<0$) likely causes departure. Our work provides a rare paradigm of manipulation near a quantum critical point in a quasi-1D Kondo lattice by uniaxial stress, and paves the way for further investigations on the unique feature of quantum criticality in the quasi-1D limit.     

十二烷基苯磺酸钠与聚乙烯吡咯烷酮复配表面活性剂对单晶硅制绒的影响

本文采用十二烷基苯磺酸钠(SDBS)与聚乙烯吡咯烷酮(PVP)的复配溶液作为单晶硅制绒添加剂,取代目前常用碱醇制绒液中的异丙醇,不仅降低了绒面的反射率、缩短了制绒时间,而且具有成本低、制绒过程中不需要定时补充等特点。本文研究了SDBS与PVP复配添加剂的比例、浓度、反应时间、反应温度等对单晶硅制绒效果的影响,实验发现当SDBS与PVP的混合体积比为1∶4、复配添加剂的浓度为0.26%(质量分数)、制绒温度为80 ℃、制绒时间为15 min时,在400~1 000 nm波长范围内的平均反射率为9.8%。与传统的碱醇制绒液相比,SDBS与PVP复配添加剂的制绒时间缩短了25 min,反射率降低约2%,是一种非常有发展潜力的产业化单晶硅制绒添加剂。