【摘 要】
：
Ultrafast optical spectroscopy of a single crystal of a Dirac semimetal CdaAs2 is carried out.An acoustic phonon (AP) mode with central frequency f =0.037 THz (
【机 构】
：
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics,Chinese Academy of Sc
论文部分内容阅读
Ultrafast optical spectroscopy of a single crystal of a Dirac semimetal CdaAs2 is carried out.An acoustic phonon (AP) mode with central frequency f =0.037 THz (i.e.,1.23cm-1 or 0.153meV) is unambiguously generated and detected,which we attribute to laser-induced thermal strain.An AP chirping (i.e.,variation of the phonon frequency) is clearly detected,which is ascribed to heat capacity variation with time.By comparing our experimental results and the theoretical model,we obtain a chirping time constant,which is 31.2ps at 6 K and 19.8ps at 300 K,respectively.Significantly,we identify an asymmetry in the AP frequency domain peak and find that it is caused by the chirping,instead of a Fano resonance.Moreover,we experimentally demonstrate that the central frequency of AP is extremely stable with varying laser fluence,as well as temperature,which endows Cd3As2 application potentials in thermoelectric devices.
其他文献
2H-and 1T-phase monolayer MoTe2 films on highly oriented pyrolytic graphite are studied using scanning tunneling microscopy and spectroscopy (STM/STS).The phase
We study the interaction of a uniform,cold and collisional plasma with a test charged particle moving off-axis at a constant speed down a cylindrical tube with
随着信息技术的不断发展,教育教学方式也随之有了许多改变。信息技术的引进,改变了单纯依靠黑板授课的历史,为小学数学的课堂教学增添了新活力。将多媒体信息技术引入小学数
We investigate how the way of breaking links and establishing links impacts cooperation by comparing four coevolutionary rules.In the rules,a player chooses to
【摘 要】众所周知，初中学生正处于青春叛逆期，心智并未成熟，很容易对学习产生抗拒心理。尤其是面对传统的教学方式时，其厌恶感十分明显。这不仅影响教学效率，对学生亦毫无益处。因此，必须调整传统的教学模式，并将“情”与“趣”融入教学内容中，才能形成愉悦的教学氛围，进而提高教学效率。基于此，本文将研究“情”与“趣”与初中化学间有何关联，再根据研究结果总结出合理的教学方式，希望本研究可推动趣味化学教学的发
随着课程改革的不断深入, 估算的重要性已经不言而喻.但是目前在估算的教与学中,依然存在不足.笔者结合自己的教学实践,对估算的含义以及价值作一阐述,并针对目前估算教学环
To reveal the saddle-type dose effect relationship,we propose a radiation mutagenesis model based on maize nutrition difference resulting from heavy ion 7Li rad
We present low-temperature magnetization,magnetoresistance and specific heat measurements on the Kondo lattice compound CePt3P under applied magnetic fields up
Thermal expansion is a common phenomenon in both metals and alloys,which is important for metallic material applications in mode industry,especially in nuclear
红外热像仪可用于工业生产现场非接触式温度测量,具有其它方法无法比拟的测温速度快、灵敏度高、范围宽以及可进行动态、远距离测温等优点。要使热像仪具有较高的性能,就必