Modesti S, Petaccia L, Ceballos G, Vobornik I, Panaccione G, Rossi G, Ottaviano L, Larciprete R, Lizzit S, Goldoni A
Laboratorio Nazionale TASC-INFM, S.S. 14 Km 163.5, 34012 Trieste, Italy.
Phys Rev Lett. 2007 Mar 23;98(12):126401. doi: 10.1103/PhysRevLett.98.126401. Epub 2007 Mar 19.
The Sn/Si(111)-(square root 3 x square root 3)R30 degrees surface was so far believed to be metallic according to the electron counting argument. We show, by using tunneling spectroscopy, scanning tunneling microscopy, photoemission, and photoelectron diffraction, that below 70 K this surface has a very low density of states at the Fermi level and is not appreciably distorted. The experimental results are compatible with the insulating Mott-Hubbard ground state predicted by LSDA+U calculations [G. Profeta and E. Tosatti, Phys. Rev. Lett. 98, 086401 (2007)].
根据电子计数理论，迄今为止人们认为Sn/Si(111)-(√3×√3)R30°表面是金属性的。我们通过隧穿光谱、扫描隧穿显微镜、光电子发射和光电子衍射表明，在70K以下，该表面在费米能级处的态密度非常低，且没有明显畸变。实验结果与LSDA+U计算[G. 普罗费塔和E. 托萨蒂，《物理评论快报》98, 086401 (2007)]预测的绝缘莫特-哈伯德基态相符。
