Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, United States of America.
Rep Prog Phys. 2017 Nov;80(11):112502. doi: 10.1088/1361-6633/aa82d2.
The emergence of complex and fascinating states of quantum matter in the neighborhood of zero temperature phase transitions suggests that such quantum phenomena should be studied in a variety of settings. Advanced technologies of the future may be fabricated from materials where the cooperative behavior of charge, spin and current can be manipulated at cryogenic temperatures. The progagating lattice dynamics of displacive ferroelectrics make them appealing for the study of quantum critical phenomena that is characterized by both space- and time-dependent quantities. In this key issues article we aim to provide a self-contained overview of ferroelectrics near quantum phase transitions. Unlike most magnetic cases, the ferroelectric quantum critical point can be tuned experimentally to reside at, above or below its upper critical dimension; this feature allows for detailed interplay between experiment and theory using both scaling and self-consistent field models. Empirically the sensitivity of the ferroelectric T 's to external and to chemical pressure gives practical access to a broad range of temperature behavior over several hundreds of Kelvin. Additional degrees of freedom like charge and spin can be added and characterized systematically. Satellite memories, electrocaloric cooling and low-loss phased-array radar are among possible applications of low-temperature ferroelectrics. We end with open questions for future research that include textured polarization states and unusual forms of superconductivity that remain to be understood theoretically.
在接近零温相变的地方出现复杂而迷人的量子物质状态，这表明应该在各种环境中研究这些量子现象。未来的先进技术可能会由材料制成，这些材料中的电荷、自旋和电流的协同行为可以在低温下进行控制。位移铁电体的传播晶格动力学使它们成为研究量子临界现象的理想选择，这种现象的特点是空间和时间相关的数量。在这篇关键问题文章中，我们旨在提供一个关于近量子相变的铁电体的自包含概述。与大多数磁性情况不同，铁电量子临界点可以通过实验调谐到、高于或低于其上临界维度；这一特性允许使用标度和自洽场模型，对实验和理论之间的详细相互作用进行研究。从经验上看，铁电 T '对外部和化学压力的敏感性为数百开尔文的温度行为提供了广泛的实际应用。可以添加和系统地表征其他自由度，如电荷和自旋。低温铁电体的潜在应用包括卫星存储器、电卡冷却和低损耗相控阵雷达。我们以未来研究的开放性问题结束，其中包括有待理论理解的织构化极化状态和异常形式的超导性。
