Interface
Energetics and Charge Carrier Density Amplification by Sn-Doping in
LaAlO<sub>3</sub>/SrTiO<sub>3</sub> Heterostructure
Safdar Nazir
Jianli Cheng
Maziar Behtash
Jian Luo
Kesong Yang
10.1021/acsami.5b02770.s001
https://acs.figshare.com/articles/journal_contribution/Interface_Energetics_and_Charge_Carrier_Density_Amplification_by_Sn_Doping_in_LaAlO_sub_3_sub_SrTiO_sub_3_sub_Heterostructure/2151418
Tailoring
the two-dimensional electron gas (2DEG) at the <i>n</i>-type
(TiO<sub>2</sub>)<sup>0</sup>/(LaO)<sup>+1</sup> interface between
the polar LaAlO<sub>3</sub> (LAO) and nonpolar SrTiO<sub>3</sub> (STO)
insulators can potentially provide desired functionalities for next-generation
low-dimensional nanoelectronic devices. Here, we propose a new approach
to tune the electronic and magnetic properties in the <i>n</i>-type LAO/STO heterostructure (HS) system via electron doping. In
this work, we modeled four types of layer doped LAO/STO HS systems
with Sn dopants at different cation sites and studied their electronic
structures and interface energetics by using first-principles electronic
structure calculations. We identified the thermodynamic stability
conditions for each of the four proposed doped configurations with
respect to the undoped LAO/STO interface. We further found that the
Sn-doped LAO/STO HS system with Sn at Al site (Sn@Al) is energetically
most favorable with respect to decohesion, thereby strengthening the
interface, while the doped HS system with Sn at La site (Sn@La) exhibits
the lowest interfacial cohesion. Moreover, our results indicate that
all the Sn-doped LAO/STO HS systems exhibit the <i>n</i>-type conductivity with the typical 2DEG characteristics except the
Sn@La doped HS system, which shows <i>p</i>-type conductivity.
In the Sn@Al doped HS model, the Sn dopant exists as a Sn<sup>4+</sup> ion and introduces one additional electron into the HS system, leading
to a higher charge carrier density and larger magnetic moment than
that of all the other doped HS systems. An enhanced charge confinement
of the 2DEG along the <i>c</i>-axis is also found in the
Sn@Al doped HS system. We hence suggest that Sn@Al doping can be an
effective way to enhance the electrical conduction and magnetic moment
of the 2DEG in LAO/STO HS systems in an energetically favorable manner.
2015-07-08 00:00:00
charge carrier density
LAO
2 DEG characteristics
interface
nonpolar SrTiO 3
HS system
Sn
2 DEG
Charge Carrier Density Amplification
STO