Quadron-polariton: a new semiconductor quasiparticle

四子极化子：一种新型半导体准粒子

• 批准号: EP/F011393/1
• 负责人: Alexey Kavokin
• 金额: $ 56.98万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FF011393%2F1
• 关键词: Quadron; polariton; new; semiconductor; quasiparticle

Contrary to real particles whose basic properties (mass, charge, spin) are stable and may be determined once and forever, the properties of quasiparticles propagating in crystals can be tuned by a proper design of crystal structures and different external factors (heating, illumination of the crystal by light, application of electric or magnetic fields). This allows for creation of new kinds of quasiparticles by relatively simple means. This project proposes a new quasiparticle which has never been observed nor theoretically described before. We call it quadron-polariton. Quadron because it is composed by four elementary quasiparticles (three electrons and one hole) and polariton because it is created by light passing its polarization to the crystal. The quadron-polaritons are expected to have truly remarkable properties. They carry a negative charge equal to two electron charges. They have an effective mass which is approximately 10000 times lighter than the free electron mass. They are spatially extended over a few wave-lengths of light. Finally, they have an integer spin and obey the statistics of Bose-Einstein therefore. That is why, we expect that quadron-polaritons should be able to form a superfluid, i.e. roughly speaking, to unify their energies and velocities. Theoretically, because of the very light mass of quadron-polaritons, their condensation may happen even at room temperature in specially designed crystal structures. The superfluid of quadron-polaritons would be charged, that is why its creation is expected by us to lead to the phenomenon of superconductivity (circulation of current without any applied voltage). Observation of light-induced superconductivity would be an extraordinary discovery also having a considerable economic effect. We are going to pave the way towards this observation by complex theoretical and experimental studies of quadron-polaritons in ultrathin artificial crystal structures.

与基本性质（质量、电荷、自旋）稳定且可以永久确定的真实粒子相反，在晶体中传播的准粒子的性质可以通过晶体结构的适当设计和不同的外部因素（加热、光照射晶体、施加电场或磁场）来调节。这允许通过相对简单的方式创建新型准粒子。该项目提出了一种以前从未被观察到或理论上描述过的新准粒子。我们称之为四方极化子。四元子是因为它由四个基本准粒子（三个电子和一个空穴）组成，而极化子是因为它是由光将其偏振传递到晶体而产生的。四子极化子预计将具有真正非凡的特性。它们带有等于两个电子电荷的负电荷。它们的有效质量大约比自由电子质量轻 10000 倍。它们在空间上延伸了几个光波长。最后，它们具有整数自旋，因此服从玻色-爱因斯坦统计。这就是为什么，我们期望四子极化激元应该能够形成超流体，即粗略地说，统一它们的能量和速度。理论上，由于四子极化子的质量非常轻，即使在室温下，它们在特殊设计的晶体结构中也可能发生凝结。四子极化子的超流体会带电，这就是为什么我们期望它的产生会导致超导现象（没有任何施加电压的电流循环）。观察光诱导的超导性将是一个非凡的发现，也具有相当大的经济效应。我们将通过对超薄人造晶体结构中的四子极化子进行复杂的理论和实验研究，为这一观察铺平道路。