Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The role of double TiO2 layers at the interface of FeSe/SrTiO3
  superconductors   We determine the surface reconstruction of SrTiO3 used to achieve
superconducting FeSe films in experiments, which is different from the 1x1 TiO2
terminated SrTiO3 assumed by most previous theoretical studies. In particular,
we identify the existence of a double TiO2 layer at the SrTiO3-FeSe interface
that plays two important roles. First, it facilitates the epitaxial growth of
FeSe. Second, ab initio calculations reveal a strong tendency for electrons to
transfer from an oxygen deficient SrTiO3 surface to FeSe when the double TiO2
layer is present. As a better electron donor than previously proposed
interfacial structures, the double layer helps to remove the hole pocket in the
FeSe at the {\Gamma} point of the Brillouin zone and leads to a band structure
characteristic of superconducting samples. The characterization of the
interface structure presented here is a key step towards the resolution of many
open questions about this novel superconductor.

19
The categories of this paper are: eess
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph