Doping Variation of Optical Properties in ZrNCl Superconductors

作者：Takano Takumi^*; Kasahara Yuichi; Oguchi Tamio; Hase Izumi; Taguchi Yasujiro; Iwasa Yoshihiro

来源：Journal of the Physical Society of Japan, 2011, 80(2): 023702.

DOI：10.1143/JPSJ.80.023702

• superconductivity
• optical reflectivity
• electronic structure
• first-principles calculation

Systematic optical reflectivity measurements were performed on a series of electron-doped layered nitride LixZrNCl superconductors with a variable carrier density. A Drude band grew up with increasing Li doping level x, providing optical evidence of a transition from a band insulator to a metal. The doping variation of the plasma edge exhibited excellent agreement with the results of first-principles calculations. Furthermore, the good agreement among the optical, thermal, and theoretical effective masses highlights the uniqueness of the present materials, indicating that relatively high T-c superconductivity with T-c similar to 15 K can emerge from a light effective mass m* similar to 0.9 m(0) with minimal renormalization.

• 出版日期2011-2