Department of Physics, University of Texas, Austin, Texas 78712, USA.
Phys Rev Lett. 2013 May 24;110(21):217203. doi: 10.1103/PhysRevLett.110.217203. Epub 2013 May 20.
We employed a scanning tunneling microscope to image the (001) surface topography and local density of states (LDOS) in La(2-2x)Sr(1+2x)Mn(2)O(7) (x=0.32, LSMO) single crystals below the Curie temperature (T(C)≈120 K). The LDOS maps revealed a stripelike modulation propagating along the tetragonal a axis with a wavelength of about 16 Å, which is indicative of a charge density wave (CDW). The observed CDW in the x=0.32 sample is far from the Fermi surface nesting instability as compared with the data of angle resolved photoemission spectroscopy in an x=0.40 sample. The stripe model developed previously for cuprates can explain the observed CDW in our LSMO sample, indicating that competing interactions between localized and itinerant phases are the origin of the spatial modulations present intrinsically in cuprates and manganites.
我们使用扫描隧道显微镜来成像 La(2-2x)Sr(1+2x)Mn(2)O(7)（x=0.32，LSMO）单晶体在居里温度（T(C)≈120 K）以下的（001）表面形貌和局域态密度（LDOS）。LDOS 图谱显示出沿四方晶系 a 轴传播的条纹状调制，其波长约为 16 Å，这表明存在电荷密度波（CDW）。与 x=0.40 样品的角分辨光电子能谱数据相比，x=0.32 样品中的观察到的 CDW 远未达到费米面嵌套不稳定性。以前为铜酸盐开发的条纹模型可以解释我们在 LSMO 样品中观察到的 CDW，表明局域和巡游相之间的竞争相互作用是铜酸盐和锰氧化物中存在的空间调制的内在起源。
