Science of Nano-Wire Metal Complexes with Strong Electron-Correlation

由于电子-声子相互作用，准一维卤素桥接Pd化合物呈现Pd(II)-Pd（IV）混合价态或电荷密度波态或佩尔斯绝缘体。为了实现Pd(III) mot绝缘子，我们使用了长烷基链的磺酸反阴离子。在五烷基链原料中，Pd化合物在约200K时发生了从Pd(II)-Pd(IV) peerls绝缘子到Pd(III) mot -绝缘子的相变，且存在滞后，为逆peerls相变。用ESR、x射线单晶分析、单晶反射光谱、电导率等证明了这一现象。在十烷基链和十二烷基链的情况下，Pd（III）莫特绝缘体即使在室温下也处于基态，这是第一个例子。这些有趣的现象很好地解释了固定效应或长烷基链的化学压力。在15 K的Pd(III) mot -Insulator中，电荷转移带能量（0.5eV）的光照射产生Pd(II)-Pd(IV) peerls绝缘子态，而L5 eV的光照射产生金属态。这种光致相变发生在飞秒内，可用于超高速光通信。

Quasi-one-dimensional halogen-bridged Pd compounds take a Pd(II)-Pd(IV) mixed-valence state or charge-density-wave state or Peierls Insulator due to the electron-phonon interaction. In order to realize a Pd(III) Mott-Insulator we used the sulphonic acid counter anions with long alkyl chains. In the raw of the five alkyl chain, the Pd compound shows the phase transition from the Pd(II)-Pd(IV) Peierls Insulator into the Pd(III) Mott-Insulator about 200K with hysteresis, which is the inverse Peierls transition. This phenomena were evidenced by ESR, X-ray single-crystal analyses, single-crystal reflection spectra, electrical conductivities, etc. In the case of the ten and twelve alkyl chains, the Pd(III) Mott-insulators are the ground state even in mom temperature, which is the first example. These interesting phenomena are well explained by the fastener effect or chemical pressure of the long alkyl chains. In the Pd(III) Mott-Insulator at 15 K the photo-irradiation with the energy of the charge transfer band (0.5eV) produced the Pd(II)-Pd(IV) Peierls Insulator state, while the photo-irradiation with L5 eV produced the metallic state. Such photo-induced phase transitions occurred in femto-seconds, which are available for the ultra-fast optical communication.