Photoemission study of (V1-xMx)2O3 (M=Cr,Ti)
Photoemission study of (V1-xMx)2O3 (M=Cr,Ti)
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DOI：
10.1103/physrevb.74.165101
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发表时间：
2006-10-01
影响因子：
3.7
通讯作者：
Metcalf, P.
中科院分区：
文献类型：
--
作者：
Mo, S. -K.;Kim, H. -D.;Metcalf, P.
本文报道了（V_（1-x）M_x）（2）O_（3-）（M=Cr，Ti）的高分辨体敏光电子能谱。对（V1-xMx）（2）O-3的顺磁金属（PM）、顺磁绝缘体（PI）和反铁磁绝缘体（AFI）相进行了测量，其中Cr掺杂的样品x=0，0.012和0.028，Ti掺杂的样品x=0.01。在PM阶段，我们观察到一个突出的准粒子峰一般与理论，结合动力学平均场理论与局部密度近似（LDA+DMFT）。准粒子峰的峰宽和峰重明显大于理论值。对于PI和AFI相，钒的3d部分的价谱不是简单的单峰结构。对于PI相，还没有对这些结构有很好的理论理解。当PI到AFI跃迁发生时，电子移除间隙的大小增加，并且光谱权重在更接近化学势的能量范围内累积。在相同的相位与不同的组合物的光谱显示有趣的单调变化，作为掺杂剂浓度的增加，无论掺杂剂的种类。随着Cr掺杂量的增加，AFI相隙减小，PI相隙增大。
We present high-resolution bulk-sensitive photoemission spectra of (V1-xMx)(2)O-3 (M=Cr,Ti). The measurements were made for the paramagnetic metal (PM), paramagnetic insulator (PI), and antiferromagnetic insulator (AFI) phases of (V1-xMx)(2)O-3 with the samples of x=0, 0.012, and 0.028 for Cr doping and x=0.01 for Ti doping. In the PM phase, we observe a prominent quasiparticle peak in general agreement with theory, which combines dynamical mean-field theory with the local density approximation (LDA+DMFT). The quasiparticle peak shows a significantly larger peak width and weight than in the theory. For both the PI and AFI phases, the vanadium 3d parts of the valence spectra are not simple one peak structures. For the PI phase, there is not yet a good theoretical understanding of these structures. The size of the electron removal gap increases, and spectral weight accumulates in the energy range closer to the chemical potential, when the PI to AFI transition occurs. Spectra taken in the same phases with different compositions show interesting monotonic changes as the dopant concentration increases, regardless of the dopant species. With increased Cr-doping, the AFI phase gap decreases and the PI phase gap increases.