Hanghui

My name is Hanghui Chen. I went to college of Peking University, China and got my B.S. degree in 2004.

I joined Sohrab's group in May, 2007. I am now working on novel properties of LaAlO₃/SrTiO₃ interface. In 2004, in a pioneering paper [1], Ohtomo and Hwang found that a high mobility gas can be formed at the LaAlO₃/SrTiO₃ heterointerface. After that more novel properties of this heterointerface have been discovered, including its tunable electric-field response [2], induced magnetism [3] and superconductivity at low temperature [4].

However, though various intriguing properties have been investigated in experiments, the mechanism of high conductitivity at the interface of two insulating oxides is still under heated debate. Up till now it is believed that two mechanisms play an important role. One is intrinsic, so-called 'polar catastrophe' which is due to polar discontinuities at the interface [1, 5]. The other is extrinsic, so-called 'oxygen vacancies' which is induced in the growth process [6, 7, 8].

I want to use DFT method to understand different roles of these two mechanisms play at the interface and how to 'separate' them in experiments.

[1] A. Ohtomo, H. Y. Hwang. Nature 427, 423 (2004)

[2] S. Thiel, G. Hammerl, A. Schmehl, C. W. Schneider, J. Mannhart, Science 313, 1942 (2006)

[3] A. Brinkman, et al., Nat. Mater. 6, 493 (2007)

[4] N. Reyren, et al., Science 317, 1196 (2007)

[5] N. Nakagawa, H. Y. Hwang and D. A. Muller, Nat. Mater. 5, 204 (2006)

[6] A. S. Kalabukhov, Phys. Rev. B 75, 235417 (2007)

[7] W. Siemons, Phys. Rev. Lett 98, 196802 (2007)

[8] G. Herranz, Phys. Rev. Lett 98, 216803 (2007)