Indexed on: 13 Jun '17Published on: 13 Jun '17Published in: Journal of physics. Condensed matter : an Institute of Physics journal
We report the photoemission spectroscopy studies on the newly discovered two dimensional electron gas (2DEG) system LaTiO<sub>3</sub>/KTaO<sub>3</sub>, whose interfacial carriers shows much higher mobility than that in LaAlO<sub>3</sub>/SrTiO<sub>3</sub> at room temperature, thus raising the application prospect of transition metal oxide-based 2DEG. By measuring the density of states at the Fermi energy (E<sub>F</sub> ), we directly reveal the spatial distribution of the conducting electrons at the interface. The density of states near E<sub>F</sub> of the topmost LTO reaches the highest when LTO is 2-unit-cell thick, and diminishes at the 5th unit cell of LTO. We discussed the origin of such a spacial distribution of conducting electrons and its relation with 2DEG, and proposed two possible scenarios based on electrostatic relaxations and chemical reconstructions. These results offer experimental clues in understanding the characteristics and origin of the 2DEG, and also shed light on improving the performance of 2DEG.