论文标题
在压力下元素柜中相变和结构调制的光学签名
Optical signatures of phase transitions and structural modulation in elemental tellurium under pressure
论文作者
论文摘要
据报道，在能量范围为0.015-2 eV的压力下，对元素校库的室温红外光谱研究。 Optical signatures of the high-pressure polymorphs are investigated and compared to the results of density-functional band-structure calculations.首先在3.5 GPa的光导率中看到了DRUDE峰，表明三角形TE-I内的半导体到金属过渡。在4.3 GPA左右，DRUDE光谱重量和DC导电率的急剧增加表示向三斜骨TE-II多晶型物的转化。在0.15 eV附近的吸收峰出现在5 GPA以上，与TE-II逐渐转化为结构相似但不相同的TE-III。从显微镜上讲，该峰只能在足够大的相称的近似物中重现，这表明低能响应是结构调制的指纹。
A room-temperature infrared spectroscopy study of elemental tellurium at pressures up to 8.44 GPa in the energy range 0.015-2 eV is reported. Optical signatures of the high-pressure polymorphs are investigated and compared to the results of density-functional band-structure calculations. A Drude peak is first seen in the optical conductivity around 3.5 GPa indicating a semiconductor-to-metal transition within trigonal Te-I. A sharp increase in the Drude spectral weight and dc-conductivity around 4.3 GPa signals the transformation toward the triclinic Te-II polymorph. An absorption peak around 0.15 eV appears above 5 GPa concomitant with the gradual transformation of Te-II into the structurally similar but incommensurately modulated Te-III. Microscopically, this peak can only be reproduced within a sufficiently large commensurate approximant, suggesting the low-energy optical response as a fingerprint of the structural modulation.
