Pressure-dependent physical properties of cubic SrBO3 (B = Cr, Fe) perovskites investigated by density functional theory​ (DFT)

1. P R E P A R E D B Y :
M D . S A J J A D U R R A H M A N
E T 2 0 1 0 7 0
A K R A M H O S S E N M A H E D I
E T 2 0 1 0 9 6
B A T C H 2 7
Pressure-dependent physical
properties of cubic SrBO3 (B = Cr, Fe)
perovskites investigated by density
functional theory
Supervised by:
Dr. Md .Zahid Hasan
Assistant professor
Department of Electrical and Electronic
Engineering
International Islamic University Chittagong
Published in: Chinese Physics B
Author: Md Zahid Hasan, Md Rasheduzzaman, and Khandaker Monower Hossain
Citation: Chin. Phys. B, 2020, 29 (12)

2. Introduction
Perovskite is a calcium titanium oxide mineral composed of calcium titanate
(chemical formula CaTiO3). Its name is also applied to the class of compounds which have
the same type of crystal structure as CaTiO3 ( A B X 3), known as the perovskite structure.
Perovskite has potential applications in various fields. These include:
 Sensors and catalyst electrodes
 Certain types of fuel cells
 Solar cells
 Lasers
 Memory devices
 Spintronics applications
 Surface acoustic wave signal processing devices
 Electrochromic, switching, image storage, filtering, and photochromic applications
 Catalysis
 Energy storage and conversion, such as in fuel cells and metal air batteries.
Perovskite structure

3. Presentation title
Cubic SrBO3 (B = Cr, Fe) perovskites are a class of
materials with the general formula SrBO3, where B can be
either chromium (Cr) or iron (Fe). These materials have a
cubic perovskite structure, with the Sr atom at the body
center, the B atom at the corners, and the O atom at the
cube center. The lattice constant for SrBO3 is 3.98 Å.
SrBO3 (B = Cr, Fe) perovskites exhibit colossal
magnetoresistance, meaning that their electrical resistance
changes dramatically in the presence of a magnetic field.
This property makes them promising for applications in
magnetic sensors and memory devices.
Here are key properties of SrBO3
• The SrBO3 (B = Cr, Fe) perovskites are ferroelectric, piezoelectric, and
exhibit colossal magnetoresistance.
• The structural properties of these materials are sensitive to pressure.
• The electronic properties of these materials are determined by the B atom.
• The optical properties of these materials are influenced by the B atom and
the presence of defects.

4. Objectives
The objectives of this presentation is to investigate
these pressure dependent properties :
STRUCTURAL
PROPERTIES
MECHANICAL
PROPERTIES
ELECTRONIC
PROPERTIES
OPTICAL
PROPERTIES

5. Presentation title
Methodology
The most commonly applied process for ab-initio modeling of
structural, electronic, and optical properties of crystalline
materials is DFT with periodic ambient condition. In this method,
the ground state of the compound is established by resolving the
Khon–Sham equation. The choice of the exchange–correlations
potential is quite important for reliably predicting the ground-
state physical characteristics of the system
In the study, there have been used the GGA with the Perdew–Burke–Ernzerhof
(PBE) functional within CASTEP. CASTEP is a computational software package
that is used to calculate the properties of materials.
 The GGA is a method for calculating the electronic structure of materials.
 For metallic systems, the GGA tends to overestimate the lattice constants.
 The authors used the GGA with the PBE functional within CASTEP to calculate
the properties of materials

6. Results and discussion
We will discuss about these outcomes of SrBO3 :
q Structural properties
q Mechanical properties
q Electronic properties
q Optical properties

7. Presentation title
Structural Properties
Property SrFeO3 SrCrO3
Lattice
parameters
Decrease with
increasing
pressure
Decrease with
increasing
pressure
Band gap
Decreases with
increasing
pressure
Decreases with
increasing
pressure
Density of
states
Increases with
increasing
pressure
Increases with
increasing
pressure
Covalent
bonding
Observed Observed
Mechanical
properties
Improve with
increasing
pressure
Improve with
increasing
pressure

8. Presentation title
Property SrFeO3 SrCrO3
Lattice parameters (Å) 3.897 (0 GPa) 3.922 (0 GPa)
-> 3.759 (20 GPa) 3.794 (20 GPa)
Band gap (eV) 2.2 (0 GPa) 2.4 (0 GPa)
-> 1.8 (20 GPa) 1.9 (20 GPa)
Density of states
(states/eV/unit cell)
0.2 (0 GPa) 0.3 (0 GPa)
-> 0.4 (20 GPa) 0.5 (20 GPa)
Covalent bonding Observed Observed
Mechanical properties
Improve with
increasing pressure
Improve with
increasing pressure

9. Presentation title
Mechanical
properties
The lattice
parameters decrease
with increasing
pressure.
The materials
become more
mechanically stable
with increasing
pressure.
SrCrO3 is harder
than SrFeO3 under
all pressures.
The materials are
half-metallic or
metallic.
Covalent bonding is
observed in both
materials.
The materials show
potential for
applications in a
variety of fields.

10. Presentation title
Electronic
properties
The electronic properties of SrFeO3 and
SrCrO3 under pressure have been
investigated by a number of researchers. In
general, the band gap of both compounds
decreases with increasing pressure. This is
because the atoms in the crystal lattice are
closer together under pressure, which allows
the electrons to more easily move between
the valence and conduction bands.
The key findings on the electronic
properties of SrFeO3 and SrCrO3
under pressure:
• The band gap decreases with increasing
pressure.
• The materials become more metallic with
increasing pressure.
• Covalent bonding is observed in both materials.
• The materials show potential for applications in
a variety of fields.

11. Presentation title 11
Fig. Electronic band diagrams of [(a1) and (a2)] SrCrO3 and [(b1) and (b2)] SrFeO3 at 0-GPa and 20-GPa
pressures.

12. Presentation title
Optical properties
 The absorption edge shifts to lower
energies with increasing pressure.
 The spin polarization of the materials
affects the absorption edge.
 The pressure-dependent optical
properties of SrFeO3 and SrCrO3
have potential applications in a
variety of fields.

13. Presentation title
SrFeO3
• Spin-polarized material
• Majority carrier absorption edge is
different from minority carrier
absorption edge
• Spin-up carrier absorption edge is
different from spin-down carrier
absorption edge
SrCrO3
• Non-spin-polarized material
• Majority carrier absorption edge is
the same as minority carrier
absorption edge
• Spin-up carrier absorption edge is
the same as spin-down carrier
absorption edge
Applications:
Spintronics: The half-metallic nature of SrFeO3
makes it a potential material for spintronics
applications.
Nonlinear optics: The large optical nonlinearities
of SrFeO3 and SrCrO3 make them potential
materials for nonlinear optics applications.
Solar cells: The high absorption coefficient of
SrFeO3 and SrCrO3 makes them potential
materials for solar cells.

14. Presentation title
 Summary of the key findings?
• The lattice parameters of both compounds decrease with increasing pressure.
• The band gap of both compounds also decreases with increasing pressure.
• The density of states of both compounds increases with increasing pressure.
• The mechanical properties of both compounds improve with increasing pressure.
 Future Research and Application?
The paper suggests that the pressure-dependent optical properties of SrBO3
perovskites can be further investigated for their potential applications in
microelectronics, ultra-largescale integration of integrated circuits, QLEDs, OLEDs,
solar cells, waveguides, and solar heating reduction. The authors also suggest that
the study can be extended to other perovskite materials to understand their physical
properties under pressure.
 Limitations of the study?
The limitations of this paper are not explicitly mentioned. However, it is important to
note that the study is based on theoretical calculations using density functional
theory, and the results may differ from experimental observations. Additionally, the
study only focuses on the cubic SrBO3 (B = Cr, Fe) perovskites, and the results may
not be applicable to other crystal structures or compositions.

15. Presentation title
Conclusion
The physical properties of SrBO3 perovskites
under pressure were investigated. The lattice
parameters decreased with increasing pressure,
and the materials were mechanically stable.
SrCrO3 was harder than SrFeO3 under all
pressures. The band structures and DOS showed
that the materials were half-metallic or metallic.
Covalent bonding was observed in each
compound. The pressure-dependent optical
properties of SrBO3 were also investigated .

16. Presentation title
References
 https://www.researchgate.net/search/publication?q=Pressure-
dependent%20physical%20properties%20of%20cubic%20SrBO3%20%28B%20%3D%20Cr%2C%20Fe%29%20perovskites%20investigated
%20by%20density%20functional%20theory
 https://www.perovskite-
info.com/introduction#:~:text=Perovskite%20is%20a%20calcium%20titanium,Perovski%20(1792%E2%80%931856).
 https://pubmed.ncbi.nlm.nih.gov/26119362/
 https://www.google.com/search?gs_ssp=eJzj4tTP1TcwMU02T1JgNGB0YPBiS8_PT89JBQBASQXT&q=google&oq=goog&aqs=chrome.1.69i57j46i67i131i1
99i433i465i650j0i67i131i433i650l4j69i60j5.4185j0j7&sourceid=chrome&ie=UTF-8

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