Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surface geometry determined temperature-dependent band structure
  evolutions in organic halide perovskite single crystals   In this study, different electronic structure evolutions of perovskite single
crystals are found via angle-resolved photoelectron spectroscopy (ARPES): (i)
unchanged top valence band (VB) dispersions under different temperatures can be
found in the CH3NH3PbI3, (ii) phase transitions induced the evolution of top VB
dispersions, and even a top VB splitting with Rashba effects can be observed in
the CH3NH3PbBr3. Combined with low-energy electron diffraction (LEED),
metastable atom electron spectroscopy (MAES), and DFT calculation, we confirm
different band structure evolutions observed in these two perovskite single
crystals are originated from the cleaved top surface layers, where the
different surface geometries with CH3NH3+-I in CH3NH3PbI3 and Pb-Br in
CH3NH3PbBr3 are responsible for finding band dispersion change and appearing of
the Rashba-type splitting. Such findings suggest that the top surface layer in
organic halide perovskites should be carefully considered to create functional
interfaces for developing perovskite devices.

15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
2
The categories of this paper are: math
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph