Two different ground states in K-intercalated polyacenes
Two different ground states in K-intercalated polyacenes
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DOI：
10.1103/physrevb.93.075130
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发表时间：
2016-02
影响因子：
3.7
通讯作者：
Quynh T N Phan;S. Heguri;H. Tamura;T. Nakano;Y. Nozue;K. Tanigaki
中科院分区：
文献类型：
--
作者：
Quynh T N Phan;S. Heguri;H. Tamura;T. Nakano;Y. Nozue;K. Tanigaki
研究了四种最小分子萘（NN）、蒽（AN）、并四苯（TN）和并五苯（PN）的钾（K）插层多环芳烃（PLA）[polyacene PLA]的电子态，着重于它们的1：1化学计量相.通过磁性、振动和光学测量，在第一组[和]和第二组[和]之间确定了明确的实验差异。第一组被归类为莫特绝缘体与反铁磁基态的能量为1000毫电子伏，而第二组被归类为带绝缘体通过二聚体形成由于自旋佩尔斯不稳定性。在后者的系统中，第一个热可访问的三重态位于远离单重基态，并没有检测到电子自旋共振光谱，直到300 K是非常不同的观察到的空穴掺杂的PN报告较早。结果给出了一个新的系统的理解电子掺杂PLA的电子状态敏感的能量平衡之间的网站库仑排斥，带宽，和Peierls不稳定性。
The electronic states of potassium- (K-) intercalated zigzag-type polycyclic aromatic (PLA) hydrocarbon [polyacene PLAs]are studied for a series of the four smallest molecules: naphthalene (NN), anthracene (AN), tetracene (TN), and pentacene (PN), focusing on their 1:1 stoichiometric phases. Clear experimental differences are identified between the first group [and] and the second group [and] by magnetic, vibrational, and optical measurements. The first group is categorized as a Mott insulator with an antiferromagnetic ground state with energy of ∼10 meV, whereas the second group is classified as a band insulator via dimer formation due to the spin Peierls instability. In the latter system, the first thermally accessible triplet states are located far apart from the singlet ground states and are not detected by electron spin-resonance spectroscopy until 300 K being very different from what is observed for the hole-doped PN reported earlier. The results give a new systematic understanding on the electronic states of electron-doped PLAs sensitive to the energetic balance among on-site Coulomb repulsion, bandwidth, and the Peierls instability.