Pressure-dependent optical investigations of α -(BEDT-TTF) 2 I 3 : Tuning charge order and narrow gap towards a Dirac semimetal
Pressure-dependent optical investigations of α -(BEDT-TTF) 2 I 3 : Tuning charge order and narrow gap towards a Dirac semimetal
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α -(BEDT-TTF) 2 I 3 的压力相关光学研究：调整电荷顺序和窄带隙朝向狄拉克半金属
DOI：
10.1103/physrevb.93.195116
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发表时间：
2016
影响因子：
3.7
通讯作者：
M. Dressel
中科院分区：
文献类型：
--
作者：
R. Beyer;A. Dengl;T. Peterseim;S. Wackerow;T. Ivek;A.V. Pronin;D. Schweitzer;M. Dressel
红外光学研究已进行了光谱范围从80至下至温度低至10 K，通过施加静水压力。在金属状态下，K，我们观察到的德鲁德贡献增加了50%，以及中红外波段由于不断增长的分子间轨道重叠与压力高达11千巴。在有序状态下，我们提取了每个分子的电子电荷如何随温度和压力变化：传输和光学研究表明，电荷有序和金属-绝缘体转变相一致，并始终产生转变温度的线性下降由K/kbar。随着压强的增加，电荷畸变减小/kbar，带间光学带隙减小/kbar。在我们的高压和低温实验中，我们确实观察到了大量电荷载流子以及无质量电子对低频光学电导率的贡献，但是，无法明确地解开它们。
Infrared optical investigations ofhave been performed in the spectral range from 80 todown to temperatures as low as 10 K by applying hydrostatic pressure. In the metallic state,K, we observe a 50% increase in the Drude contribution as well as the mid-infrared band due to the growing intermolecular orbital overlap with pressure up to 11 kbar. In the ordered state,, we extract how the electronic charge per molecule varies with temperature and pressure: Transport and optical studies demonstrate that charge order and metal-insulator transition coincide and consistently yield a linear decrease of the transition temperaturebyK/kbar. The charge disproportionationdiminishes by/kbar and the optical gapbetween the bands decreases with pressure by/kbar. In our high-pressure and low-temperature experiments, we do observe contributions from the massive charge carriers as well as from massless electrons to the low-frequency optical conductivity, however, without being able to disentangle them unambiguously.