RUI: Quantum Criticality in Rare-Earth and Actinide-Based Intermetallics

RUI：稀土和锕系金属间化合物的量子临界性

• 批准号: 1006118
• 负责人: George Schmiedeshoff
• 金额: $ 27万
• 依托单位: Occidental College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1006118&HistoricalAwards=false
• 关键词: RUI; Quantum; Criticality; Rare; Earth

****NON-TECHNICAL ABSTRACT****Classical phase transitions, such as the freezing or boiling of water, involve heat energy. This individual investigator award will support a study of quantum phase transitions which occur at absolute zero where there is no heat. Zero-point energy, associated with the Heisenberg Uncertainty Principle, plays the role of heat in these transitions. Quantum phase transitions can dramatically affect the behavior of matter at surprisingly high temperatures and lead to characteristic changes in volume as the temperature or a magnetic field changes. A high-precision technique, developed with NSF support, will be used to search for these characteristic changes in volume in order to identify and characterize the underlying quantum phase transition. Novel states of matter that may occur near quantum phase transitions will be sought out and studied. Undergraduate students will participate in all aspects of this work, both on-campus and during trips to national laboratories and other collaborating institutions. ****TECHNICAL ABSTRACT****This individual investigator award will support a study of quantum criticality in several rare-earth and actinide-based intermetallic compounds. The thermal expansion and magnetostriction of these materials will be measured using a capacitive dilatometer developed with NSF support. Phase diagrams will be mapped out and phase transitions between the low temperature states of these materials will be thermodynamically characterized. These dilation measurements will be combined with existing specific heat measurements in a Gruneisen analysis to determine the volume dependence of the characteristic energies of these fascinating materials. Specific signatures of quantum criticality will be sought, such as a sign change of the thermal expansion and divergence of the Gruneisen parameter as the temperature approaches absolute zero. Novel states of matter that may occur near quantum phase transitions will be sought out and studied. Undergraduate students will participate in all aspects of this work, both on-campus and during trips to national laboratories and other collaborating institutions.

****非技术摘要****经典的相变，例如水的冻结或沸腾，涉及热能。 该个人研究员奖将支持对量子相变的研究，这种相变发生在没有热量的绝对零状态。 与海森堡不确定性原理相关的零点能量在这些转变中扮演着热的角色。 量子相变可以极大地影响物质在令人惊讶的高温下的行为，并随着温度或磁场的变化而导致体积的特征变化。 在 NSF 支持下开发的高精度技术将用于搜索这些体积特征变化，以便识别和表征潜在的量子相变。 将寻找和研究在量子相变附近可能出现的新物质态。 本科生将在校园内以及参观国家实验室和其他合作机构期间参与这项工作的各个方面。 ****技术摘要****这项个人研究员奖将支持对几种稀土和锕系金属间化合物的量子临界性的研究。 这些材料的热膨胀和磁致伸缩将使用在 NSF 支持下开发的电容式膨胀计进行测量。 将绘制出相图，并对这些材料的低温状态之间的相变进行热力学表征。 这些膨胀测量将与格鲁内森分析中现有的比热测量相结合，以确定这些迷人材料的特征能量的体积依赖性。 我们将寻找量子临界性的具体特征，例如当温度接近绝对零时热膨胀的符号变化和格鲁内森参数的发散。 将寻找和研究在量子相变附近可能出现的新物质态。 本科生将在校园内以及参观国家实验室和其他合作机构期间参与这项工作的各个方面。