Formation of Surface and Quantum-Well States in Ultra Thin Pt Films on the Au(111) Surface

Abstract

The electronic structure of the Pt/Au(111) heterostructures with a number of Pt monolayers n ranging from one to three is studied in the density-functional-theory framework. The calculations demonstrate that the deposition of the Pt atomic thin films on gold substrate results in strong modifications of the electronic structure at the surface. In particular, the Au(111) s-p-type Shockley surface state becomes completely unoccupied at deposition of any number of Pt monolayers. The Pt adlayer generates numerous quantum-well states in various energy gaps of Au(111) with strong spatial confinement at the surface. As a result, strong enhancement in the local density of state at the surface Pt atomic layer in comparison with clean Pt surface is obtained. The excess in the density of states has maximal magnitude in the case of one monolayer Pt adlayer and gradually reduces with increasing number of Pt atomic layers. The spin–orbit coupling produces strong modification of the energy dispersion of the electronic states generated by the Pt adlayer and gives rise to certain quantum states with a characteristic Dirac-cone shape.

Modification of a Shockley-Type Surface State on Pt(111) upon Deposition of Gold Thin Layers

“…Note that in the vicinity of the sans-serifΓ¯ point, these two surface bands experienced strong hybridization with the bulk-like electronic states, and its dispersion details were extremely sensitive to the calculation methods employed. For instance, in the local-density-approximation (LDA) calculations, the lower energy band dispersion was more flat, and its top was located at about 0.1 eV above the Fermi level [73,74]. Since in this work, we employ the GGA approximation for the description of the exchange-correlation potential, our dispersion of the lower energy Pt(111) surface state was closer to that obtained in [73].…”

“…Strong hybridization of these bands with the Pt bulk electronic states [73,74] did not allow the application of the Bychkov–Rashba model [75] in order to quantify the spin splitting. The detailed analysis of other surface states of clean Pt(111) surface can be found in [73,74,76,77,78].…”

“…This can be explained by the existence of an energy gap in the projected band structure of Au(111) in this region [82,83]. We would like to note that in the LDA calculations [73,74], these and other d -like states with energies above −3 eV resided at slightly lower energies, less than 0.2 eV. The maximal difference of 0.6 eV was observed at the bottom of the valence band.…”

Spin-orbit splitting of quantum well states in n -monolayer Ir/Au(111) heterostructures

“…The number of valence electrons in Ir is less by one than in Pt. Consequently, the energy positions of the Ir QWSs around E F are shifted upward in comparison with the nML-Pt/Au(111) system studied recently [54], which offers additional possibities in engineering the electronic states in such bimetallic systems. The dispersion shape and properties of the Ir-related QWSs as well as the layer-resolved density of states (LDOS) are analyzed.…”

Переход Металл-Полупроводник В Нанопленках Иттербия, Индуцированный Адсорбированными Молекулами Кислорода

“…Изучению квантовых свойств металлических пленок нанометровой толщины в настоящее время уделяется значительное внимание (см., например, [1][2][3][4]). В частности, представлены результаты исследований квантовых состояний в тонких пленках, зависимости их энергии от толщин пленок и сформулированы условия, при которых эти состояния проявляются.…”