Electronic phase competition and valence states in quasi-one-dimensional halogen-bridged metal complexes

准一维卤素桥联金属配合物（MX链）由于其具有自旋密度波（SDW）、电荷密度波（CDW）等多种电子相，而且与导电聚合物一样，MX链中也存在极化子等非线性激发，因而得到了广泛的研究。我们已经证明了电子自旋共振（ESR）是一种有用的方法来检测磁性离子（M^<3+>）的MX链，但上述测量一直局限于静态研究到目前为止。本研究的目的是建立时间分辨光激发ESR系统，并将其应用于MX分子链中激发态的探测和竞争电子相的光控制研究。首先，我们建立了时间分辨光激发ESR系统，并对具有CDW基态的MX分子链中激发态进行了研究。在Pd_2（chxn）Br_3中，我们成功地观察到了光生自旋共振（LESR）信号。 ...更多信息 ns; LESR的瞬态响应时间取决于温度为几分钟到几十分钟的量级。我们还研究了LESR与激发光强度和激发谱的关系，通过分析上述结果发现光激发自旋主要是孤子激发。In [Pt（en）_2][Pt（en）_2X_2]（ClO_4）_4（X=Cl和I），我们成功地观测到了LESR的激发光谱;发现这些光生自旋在X=Cl时是孤子，在X=I时是极化子，这与光诱导吸收等结果一致。其次，我们阐明了SDW和CDW的竞争电子相位，用混合金属MX链Ni_<1-x>Pd_x（chxn）_2X_3和Ni_<1-x>Co_x（chxn）_2X_3（XCl和Br）研究了卤素离子对电子相的取代效应。此外，我们研究了上述链的载流子性质，通过测量电阻率和热电功率，在压力下使用单晶。此外，更发达的形式的MX链，MMX链已被测量的ESR。我们首次在MMX链中探测到了平均价态和CDW相，以及交替电荷极化相的孤子激发。少

Quasi-one-dimensional halogen-bridged metal complexes (MX chains) have been studied extensively because the MX chains have various electronic phases such as spin density wave (SDW), charge density wave (CDW) etc. Moreover, nonlinear excitations such as polaron are created in the MX chains, as in conducting polymers. We have demonstrated that electron spin resonance (ESR) is a useful method to detect magnetic ions (M^<3+>) in the MX chains ; however the above measurements have been limited for static studies so far. The aim of the present research is to construct time-resolved photoexcited ESR system, and then to apply the ESR system for detecting the excitations in the MX chains and studying the photo control of the competing two electronic phases.First, we have constructed the time-resolved photoexcited ESR system and performed the studies of the excitations in the MX chains having CDW ground state. In Pd_2(chxn)Br_3 we have successfully observed LESR signals due to photogenerated spi … More ns at low temperatures ; time of the transient response of LESR is of the order of several to several ten minutes depending on temperature. We have also studied the dependence of LESR on the excitation-light intensity and excitation spectrum of LESR, and then found that soliton excitation is dominant for the photoexcited spins by analyzing the above results. In [Pt(en)_2][Pt(en)_2X_2](ClO_4)_4(X=Cl and I), we have successfully observed the excitation spectra of LESR ; these photogenerated spins are found to be solitons for X=Cl and polarons for X=I, consistent with the results of photoinduced absorption etc. Second, we have clarified the competing electronic phase of SDW and CDW, and substituent effect of halogen-ions to electronic phases by using mixed-metal MX chains Ni_<1-x>Pd_x(chxn)_2X_3 and Ni_<1-x>Co_x(chxn)_2X_3(XCl and Br). Moreover, we have studied carrier properties of the above chains by measuring resistivity and thermoelectric power using single crystals under pressure. Furthermore, more developed form of the MX chains, MMX chains have been measured by ESR. We have firstly detected an averaged valence and CDW phases, and soliton excitation in an alternate charge polarization phase in the MMX chains. Less