Effect of Pressure on the Superconducting Transition Temperature and Physical Properties of CaPd2P2: A DFT Investigation.

CaPd2P2 is a recently reported superconducting material belonging to the well-known ThCr2Si2-type family. First-principles density functional theory calculations have been carried out to investigate the structural, mechanical, thermophysical, optical, electronic, and superconducting properties of the CaPd2P2 compound under pressure. To the best of our knowledge, this is the first theoretical approach to studying the pressure effect on the fundamental physical and superconducting properties of CaPd2P2. It is mechanically stable under the studied pressures. The applied hydrostatic pressure reveals a noticeable impact on elastic moduli of CaPd2P2. It exhibits ductile nature under the studied pressure. Significant anisotropic behavior of the compound is revealed with/without pressure. The study of melting temperature shows that the compound has a higher melting temperature, which increases with the increasing applied pressure. The investigation of the electronic properties strongly supports the optical function analysis. The reflectivity as well as the absorption spectra shifts to higher energy with the increasing applied pressure. The pressure-dependent behavior of the superconducting transition temperature, T c, is revealed with a pressure-induced increasing trend in Debye temperature.

Introduction

The world technology is being developed every day through advanced levels of research activities to make human life easier. Superconductivity is one of the most fascinating discoveries to make the real world faster, but it is still puzzling for the research community even more than 100 years after its invention.[1] Most of the superconductors exhibit low-temperature superconductivity. Therefore, the practical application of superconducting materials is difficult. Considering this, researchers in the field of superconductivity have been developing materials with room-temperature superconductivity. In recent years, several research works have been performed to achieve room-temperature superconductivity.[2−18] Most of these researches were performed under high pressure.[2−12] In 2020, Snider et al.[5] claimed to have achieved room-temperature superconductivity in a carbonaceous sulfur hydride under high pressure (267 ± 10 GPa), providing a ray of hope. Although their research raises several questions,[19−23] it has provided a new thrust to the researchers in this field to search for new materials with high-temperature superconductivity. In 2020, Blawat et al. observed superconductivity at the transition temperatures, Tc, of nearly 1.0 and ∼0.7 K in CaPd2P2 and SrPd2P2 compounds, respectively.[24] In 2021, Islam and Hossain theoretically proved low-temperature superconductivity in CaPd2P2 and SrPd2P2.[25] Both of these are one of the 700 members of the ThCr2Si2-type materials (also called the 122 family) and exhibit fascinating chemical and physical properties.[26] The ThCr2Si2-structure was introduced in 1965 by Ban and Sikirica.[27] The APd2P2 class was first reported in 1983.[28] The ThCr2Si2-type AT2X2 (where A = lanthanide or alkaline earth elements; T = transition metals; X = P, Se, Si, Ge, or As) crystals have gained massive attention of the research community due to their diverse properties such as superconductivity at low Tc(29,30) and high Tc,[31,32] pressure-induced superconductivity,[33−36] superconductivity generated by doping,[37−39] and magnetic and anti-ferromagnetic characteristics.[40,41] In 2021, Parvin and Naqib exhibited the pressure effect on low-temperature pnictide superconductor NaSn2P2.[42] They predicted the pressure-dependent characteristics of Tc with a pressure-induced variation in the Debye temperature.

The knowledge of mechanical properties is required to know the suitability of a compound for application in a particular device. The study of the thermophysical properties, which reveals the behavior of a compound at different temperatures and pressures, is also very important. In addition, an investigation of the optical properties provides valuable information that can support to design of optoelectronic devices. The study of the electronic band structure and the density of states at the Fermi level is particularly important for gaining useful information about the parameters responsible for making a material a superconductor. The application of hydrostatic pressure is an efficient and environmental-friendly thermodynamic approach for altering the physical properties of materials. The elastic constant provides valuable information about mechanical stability, bonding strength, and stiffness of solid materials. Therefore, the pressure-dependent behavior of elastic constants is quite important to investigate. The pressure-induced variation in the elastic anisotropy of a crystal is required to gather information about any possible microcracks/defects that develop in a crystal with applied pressure.

To the best of our knowledge, none of the fundamental physical properties mentioned in the above section has been studied yet in detail for the recently reported ThCr2Si2-type CaPd2P2 compound. Therefore, the present approach deals with a detailed theoretical investigation of the structural, mechanical, electronic, optical, thermophysical, and superconducting properties of CaPd2P2 under pressure using density functional theory (DFT)-based Cambridge serial total energy package (CASTEP) code. The comprehensive calculations and new findings displayed in this research provide valuable insight into the probable applications of CaPd2P2 in the future. The authors believe that this study would be useful enough for designing as well as carrying out research on superconducting materials under pressure.

Computational Methods

In this investigation, CASTEP computer code[43] based on DFT[44,45] was used for the geometry optimization and investigation of properties. A generalized gradient approximation (GGA) along with the Perdew–Burke–Ernzerhof (PBE) method[46] was employed for this study. Vanderbilt[47] ultrasoft pseudopotential was used for the description of the electron–ion interaction. The pseudo-atomic calculations were performed by taking only valance electrons. The k-points 16 × 16 × 7 along with the cutoff energy 700 eV were chosen for this DFT investigation. The Monkhorst–Pack schemes[48] were used for the Brillouin zone sampling of k-points. The Broyden–Fletcher–Goldfarb–Shanno (BFGS) technique[49] was inserted to ensure the optimized structure of the CaPd2P2 compound. The elastic constants of CaPd2P2 were computed using the “stress–strain” theory.[50] The strain amplitude was fixed to 0.003. The convergence criteria were settled as follows: energy, maximum displacement, maximum stress, and maximum force; and 10–5 eV/atom, 0.001 Å, 0.05 GPa, and 0.03 eV/Å.

Results and Discussion

Structural Properties

The CaPd2P2 compound possesses a tetragonal structure along with the space group I4/mmm (no.139) of the renowned ThCr2Si2-type family. The Ca, Pd, and P atoms occupy 2a (0, 0, 0), 4d (0, 0.5, 0.25), and 4e (0, 0, 0.3882) Wyckoff sites, respectively.[24]Figure depicts the primitive cell and conventional unit cell of CaPd2P2.

Figure 1

Constructed crystal of the CaPd2P2 compound: (a) primitive cell and (b) conventional unit cell.

The optimized lattice parameters are listed in Table along with available experimental and theoretical values.[24,25] At 0 GPa, the DFT-optimized lattice parameters are well in accordance with the experimental results.[24]

Table 1

Calculated Lattice Parameters a and c and the Unit Cell Volume, V, of CaPd2P2 under Different Applied Pressures

P (GPa)	a (Å)	c (Å)	V (Å3)	ref
0 (exp.)	4.137	9.649	165.13	(24)
0 (GGA)	4.036	10.203	166.20	(25)
0	4.037	10.201	166.25	this
4	3.986	10.119	160.77	this
8	3.944	10.049	156.31	this
12	3.906	9.991	152.43	this
16	3.874	9.931	149.04	this

The decreasing trend in lattice parameters is observed with the increase in pressure, which infers that the space among the atoms is reduced. As a consequence, the repulsive effect between the atoms increases, which benefits the stiffness of crystal compression under pressure. To the best of our knowledge, this is the first theoretical approach to investigate the pressure effect on CaPd2P2; as a result, it was not possible to make a comparative analysis of this study with other investigations.

Mechanical Properties

To obtain information on the mechanical stability, bonding nature, and stiffness of solid materials, elastic constants are a key criterion. Tetragonal structures like that of CaPd2P2 consist of six different elastic constants, C11, C12, C13, C33, C44, and C66, which are tabulated in Table . The elastic constants C11 and C33 are related to the uniaxial stress (resistance to linear compression) and the other four reflect the shear-dominated responses (connected with the elasticity in shape). From Table , it can be noticed that the values of C11 and C33 are noticeably higher than those of other elastic constants under the studied pressures, which indicates that the CaPd2P2 compound cannot be compressed easily under uniaxial stress. The mechanical stability criteria[51] comprising these constants without pressure conditions are as follows.CaPd2P2 satisfies the above stability conditions, which was also observed in an earlier study at 0 GPa.[25] Moreover, CaPd2P2 is also dynamically stable, as observed in a previous study.[24] As this is the first theoretical approach to study the mechanical properties under pressure, mechanical stability is required to be observed under pressure. The mechanical stability of the tetragonal crystal under pressure can be observed from the following conditions[52−54]From Table , it can be observed that CaPd2P2 satisfies the above stability conditions under the studied pressure. The values in Table are found using the formulae from the Voigt–Reuss–Hill (VRH) averaging schemes.[55−57] The tabulated data includes bulk modulus (B), shear modulus (G), Young’s modulus (E), Pugh’s ratio (B/G), and Poisson’s ratio (v), and universal anisotropy indices AU. In Table , BV and BR denote the Voigt and Reuss approximated bulk moduli, respectively. The shear moduli approximated by Voigt and Reuss are denoted as GV and GR, respectively.

Table 2

Calculated Elastic Constants Cij (in GPa) of the CaPd2P2 Compound

P (GPa)	C11	C12	C13	C33	C44	C66	ref
0 (GGA)	161.61	84.66	80.55	218.66	57.15	39.11	(25)
0	161.65	87.72	80.52	219.99	57.10	39.67	this
4	186.70	103.50	89.40	232.59	64.56	46.45	this
8	206.49	117.20	113.77	265.85	71.06	61.03	this
12	229.61	135.45	128.15	312.48	74.80	75.91	this
16	254.16	152.82	140.53	331.30	84.03	86.47	this

Table 3

Calculated Values of Bulk Modulus, B (GPa), Shear Modulus, G (GPa), Young’s Modulus, E (GPa), Pugh’s Ratio, B/G, Poisson’s Ratio, v, and Universal Anisotropy, AU, of CaPd2P2

P (GPa)	BV	BR	B	GV	GR	G	E	B/G	v	AU	ref
0	114.82	113.10	113.96	50.42	48.36	49.39	129.47	2.31	0.31	0.23	(25)
0	115.65	114.06	114.85	50.41	48.15	49.28	129.34	2.33	0.31	0.25	this
4	130.06	129.50	129.78	56.69	54.53	55.61	145.98	2.33	0.31	0.20	this
8	152.04	150.30	151.17	62.90	60.91	61.90	163.40	2.44	0.32	0.18	this
12	172.80	170.14	171.47	70.43	67.65	69.04	182.61	2.48	0.32	0.22	this
16	189.71	187.87	188.79	77.95	74.58	76.26	201.64	2.48	0.32	0.24	this

It is known that a lower (higher) value of the bulk modulus and other elastic moduli is indicative of the soft (hard) nature of the crystal.[58−60] From Table , we can conclude that the softness of CaPd2P2 decreases with the increase in pressure, which is revealed by the gradual increase in B values. Therefore, it is more difficult to change the volume of the compound under higher pressures.

Pugh’s ratio and Poisson’s ratio are useful indicators of the ductility/brittleness of a solid. The B/G value lower than 1.75 is indicative of a brittle behavior, while the value higher than 1.75 indicates a ductile nature.[25,61] Similarly, the critical value of v is 0.26, higher than the critical value indicating ductility and those lower than the critical value indicating brittleness.[25,62] Since ductile materials are convenient for fabricating devices, it is important to understand their ductility/brittleness. According to the values tabulated in Table , the B/G and v values are all above 1.75 and 0.26, respectively, thus indicating the ductile behavior of CaPd2P2 under the studied pressure. The value of v can also be an indicator of the nature of interatomic forces present in bonding within solids.[63] Materials with atomic bonding dominated by the central force interaction have v within the range of 0.25–0.50. In this study, the v is within the domain of 0.25–0.50, indicating the dominance of a central force interaction in the atomic bonding of the crystal structure.

The shear modulus (G) is an indicator of shear resistance. At all pressures, G is less than B, which implies that shape-deforming stress should be used to control the mechanical failure mode of CaPd2P2 instead of the volume-changing stress. Young’s modulus (E) is defined as the resistance of a solid to compressive or tensile stress. The increasing values of E with the increasing pressure indicate that the ability to withstand tensile stress is increased with the increase in applied pressure.

Elastic anisotropy is a highly significant parameter of the crystalline solids. The study of anisotropy is necessarily important due to the different bonding natures along different crystallographic directions. This provides information about the possibility to generate microfractures in solid. The universal anisotropic characteristic, AU, is theoretically determined by an equation given elsewhere.[25,64] If the AU value is equal to zero, then the crystal is isotropic; any deviation signifies anisotropic nature. CaPd2P2 exhibits significant anisotropic nature under the studied pressure, which suggests that the mechanical properties of the compound depend on the direction.

Debye Temperature and Melting Temperature

The Debye temperature, θD, is a very significant thermophysical criterion of solid that indicates the highest frequency mode of vibration. It is a boundary between the low- and high-temperature regions of solid. When the temperature of the solid is higher than θD (i.e., T > θD), the vibration mode is considered to have kBT energy and in the case of T < θD, the vibration mode is expected to be at rest.[65] The low-temperature vibration is a result of acoustic vibration. The θD is related to different thermodynamic parameters such as the thermal expansion of solids, phonons, thermal conductivity, specific heat, and melting point. The superconducting transition temperature, Tc, is also largely associated with θD. As a result, the variation in the θD value with the applied pressure is highly significant for Tc. There are several approaches for evaluating θD. In the present research, θD is estimated using elastic moduli, which is considered one of the standard ways.[66] The average sound velocity (vm), transverse sound velocity (vt), and longitudinal sound velocity (vl) are related to the estimation of θD via the following equations[67−70]where kB, h, NA, M, ρ, and n indicate the Boltzmann constant, the Planck constant, Avogadro’s number, the molecular mass, the density, and the number of atoms in the unit cell, respectively. θD of CaPd2P2 is calculated up to 16 GPa, with a step of 4 GPa. The computed values of ρ, vt, vl, vm, and θD are tabulated in Table . At 0 GPa, the theoretically estimated value of θD is higher in comparison with the experimental result.[24] Precise measurement of θD is difficult; in a number of cases, experimental and theoretical values of θD show a larger variation.[71,72] The effect of pressure on θD is clearly observed in Table . It is exhibited that θD increases with the increasing applied pressure. This is the expected behavior of solid because the crystal becomes stiffer under pressure. Consequently, θD shows increasing affinity with the increasing applied pressure.

Table 4

Calculated Values of Density, ρ, Transverse Sound Velocity, vt, Longitudinal Sound Velocity, vl, Mean Sound Velocity, vm, Debye Temperature, θD, and Melting Temperature, Tm, of the CaPd2P2 Compound

pressure (GPa)	ρ (g/cc)	vl (m/s)	vt (m/s)	vm (m/s)	θD (K)	Tm	ref
0	6.29	5346.70	2802.17	3134.22	365	1166	(25)
0	6.29	5357.73	2779.05	3110.49	363	1165	this
4	6.50	5601.19	2924.95	3272.34	386	1260	this
8	6.69	5910.43	3041.81	3406.31	406	1369	this
12	6.86	6197.94	3172.40	3553.77	427	1511	this
16	7.02	6432.53	3295.94	3691.92	447	1613	this

The transformation of the solid phase into the liquid phase at a certain temperature is indicated as the melting temperature, Tm. This is another crucial thermophysical criterion of the application of a material at a particular temperature and also reflects the strength of the bond in solids. Tm is evaluated using elastic constants via the following equation[73]Tm of CaPd2P2 increases with the increase in applied pressure as displayed in Table , which is the result of the increasing trend in C11 and C33 (these two elastic constants are related to uniaxial stress) with the increase in applied pressure (Table ). The increasing affinity of Tm benefits the bond strength with the increase in applied pressure.

Optical Properties

The optical properties of material provide significant information, particularly for the application of optoelectronic devices. It is essential to study the material response to the incident electromagnetic radiation. Therefore, the fundamental optical properties such as reflectivity (R), optical absorption (α), optical conductivity (σ), real (ε1), and imaginary (ε2) parts of dielectric functions as a function of photon energy are calculated in this study. For metallic compounds, plasma energy (between 2 and 10 eV) is required for analyzing the optical functions.[25] In this study, 6 eV of plasma energy was used to study the optical functions of the CaPd2P2 compound. The optical functions are analyzed along the [100] polarization direction.

The reflectivity profile offers a crucial idea about the appropriateness of a material as a reflector. Figure a represents the pressure-induced reflectivity spectra of CaPd2P2 up to 20 eV of photon energy. Maximum reflectivity is observed at zero photon energy, which reduces sharply with the increasing photon energy, reaches a minimum near 6.5 eV. The reflectivity further increases above 6.5 eV and becomes flat over a wide range in the ultraviolet (UV) region of 9–18 eV. This result suggests that CaPd2P2 can be used as a prominent reflector in a wide range of UV radiation. It is also noticed from the analysis that the reflectivity does not change to a greater extent with the applied pressure. However, the reflectivity spectra shift to the higher energy above 18 eV with the increasing applied pressure.

Figure 2

Optical functions of (a) reflectivity, (b) optical absorption, (c) optical conductivity, (d) real part of dielectric function, (e) imaginary part of dielectric function, and (f) loss function of CaPd2P2 under different pressures.

The absorption coefficient measures the attenuation of light intensity while passing through a material. A lower absorption coefficient means more radiation can pass through the material and vice versa. The absorption profile of CaPd2P2 is depicted in Figure b. The optical absorption starts to increase with the increasing photon energy and reaches a maximum at ∼9.0 to 10 eV (upper limit of plasma energy) and then falls gradually. It is interesting to notice that up to 10 eV of photon energy, there is no significant effect of external pressure on absorption, while at photon energy >10 eV, the absorption spectra shift to the higher energy with the increasing external pressure.

The real part of the optical conductivity of the CaPd2P2 compound under high hydrostatic pressure is illustrated in Figure c for up to 20 eV of photon energy. It is noticed that the optical conductivity is maximum at the zero photon energy and then decreases sharply with the start of absorption of photons of low energies, and then further increases and reaches a peak position at ∼8 eV and then again decreases gradually with the increase in incident energy. These behaviors strongly support the metallic entity of CaPd2P2, which justifies the analysis of electronic properties and absorption profile. It is noticed that the conductivity spectra shift to the higher energy with the increasing applied pressures, which is also observed in the optical absorption profile.

Figure d,e displays the real and imaginary parts of the dielectric functions, respectively, at different external pressures of up to 20 eV of photon energy. Figure d displays that the real part of the dielectric function displays ε1 < 0 at zero photon energy as well as low photon energies, indicating the metallic nature of CaPd2P2. Previous studies by Islam[25] and Hossain showed that the ε1 value reaches unity and the ε2 value reaches approximately zero under higher photon energy, suggesting that CaPd2P2 is expected to appear as a transparent material in the high energy region. The applied hydrostatic pressure on CaPd2P2 does not influence its dielectric functions significantly. The imaginary part of the dielectric function is largely associated with the optical absorption profile.[25] As the optical absorption profile does not change significantly with the applied pressure, dielectric functions remain almost invariant with pressure.

The loss function measures the loss of energy of an electron traversing through a material. At 0 GPa, the loss function exhibits a sharp peak near about 18 eV of photon energy. The optical behavior of a metallic system changes to a dielectric-like response above the plasma energy.[42] The peak of loss function shifts to the higher energy with the increasing applied pressure, which also supports the analysis of optical absorption and reflectivity spectra. After certain photon energy (∼18 eV for the CaPd2P2 compound), the peak shifts in the direction of higher energies with the increase in applied pressure such that the number of effective electrons participating in the intraband as well as the interband transitions are reduced.[74]

Electronic Properties

The electronic band structures of solids provide significant information about their physical properties, which can be determined by the conduction and valance band electrons. The behavior of these electrons mostly depends on the characteristics of their energy dispersion along the k-spaces directions such as Z-G-X-P-N-G within the Brillouin zone. In this study, the electronic energy dispersion graph at 0 and 8 GPa pressures along the highly symmetric directions of the Brillouin zone of CaPd2P2 are analyzed and depicted in Figure . The Fermi level (EF) is displayed by the broken red line at zero of the photon energy scale. The overlap of the valance and conduction bands is observed at EF for both 0 and 8 GPa, indicating the metallic behavior of CaPd2P2.

Figure 3

Calculated electronic band structure of CaPd2P2 at 0 and 8 GPa pressure.

To get a clear insight into the electronic properties of CaPd2P2, the total density of states (TDOS) and the partial density states (PDOS) are calculated. As shown in Figure a, the calculated TDOS at the 0 GPa pressure at EF is ∼1.93 states/eV/f.u., which does not change significantly with the applied pressure. At 0 GPa, the calculated TDOS value at EF was observed to be ∼1.94 states/eV/f.u. in the earlier study, which supports the present investigation.[25] As the band structure and the TDOS do not change significantly with the applied pressure, DOS is analyzed further at 0 and 8 GPa only.

Figure 4

Calculated (a) TDOS of the CaPd2P2 compound at 0, 4, 8, 12, and 16 GPa pressure and (b) DOS of Ca, Pd, and P atoms in the CaPd2P2 compound at 0 and 8 GPa pressure.

For more theoretical insight, the DOS of individual atoms Ca, Pd, and P in the CaPd2P2 structure are observed, and depicted in Figure b. The Pd and P states are largely responsible for the emergence of DOS in the valance band near EF. At 0 GPa, the DOS of Ca, Pd, and P at EF is ∼0.41, ∼0.75, and ∼0.77 states/eV/f.u., respectively, which do not change significantly with the applied pressure. From this above observation, it is obvious that Pd and P atoms contribute most to the emergence of DOS at EF. The valance band energy between −7.5 and −2.0 eV is significantly contributed by the Pd-4d states along with a significant contribution from the P-3p states.

The valance band near EF (−2.0 to 0 eV) is highly dominated by the hybridization between the Pd-4d and P-3p states. This analysis reveals that these electrons are largely responsible for the emergence of superconductivity in CaPd2P2, which is also observed in previous investigations.[24,25] It is generally known that the copper pairs are formed by electrons with energies near the EF, in accordance with the Bardeen–Cooper–Schrieffer (BCS) theory.[75]Figure reveals that the contributions of Pd-4d and P-3p states in the valence band and Pd-4p and P-3p states at the conduction band are dominant, which also supports the previous investigation.[24,25]

Superconducting Properties

CaPd2P2 possesses low-temperature superconductivity with experimental Tc ∼1.0 K[24] and theoretical Tc of 0.33 K.[25] The Tc can be estimated using the following McMillan equation[76]where μ* and λ are the Coulomb pseudopotential and electron–phonon coupling constant, respectively. The Coulomb pseudopotential can be calculated using the TDOS values at the Fermi level, N(EF), by the following equation[77−79]The values of μ* in the range from 0.1 to 0.15 are considered physically reasonable.[24,80] From the above equation, it can be concluded that the value of μ* does not change significantly with the applied pressure as the DOS at the Fermi level, N(EF), of CaPd2P2 remains almost invariant with the increasing pressure. The λ can be defined as, λ = N(EF) Ve-ph, where Ve-ph is the electron–phonon interaction energy. As the N(EF) exhibits slight variation (Figure ) with the increasing applied pressure. Therefore, in the present study, the variation in λ depends on the possible effect on Ve-ph with the applied pressure. From the McMillan equation, it is expected that for a fixed value of λ of the CaPd2P2 compound, Tc may increase with the applied pressure due to the increasing trend of θD with pressure. This is because θD is linearly associated with Tc.

Figure 5

Calculated TDOS and PDOS (Pd, P) of CaPd2P2 under pressure.

Conclusions

First-principles DFT-based investigations have been carried out to study the structural, mechanical, thermophysical, optical, electronic, and superconducting properties of the ThCr2Si2-type tetragonal compound CaPd2P2 under pressure. The lattice parameters as well as the unit cell volume decrease with the applied pressure, which is the result of reducing space among the atoms with the increasing pressure. The elastic moduli show an increasing trend with the increasing pressure, which indicates that CaPd2P2 becomes increasingly stiff with the applied pressure. The study of Pugh’s ratio and Poisson’s ratio exhibits that CaPd2P2 has a ductile nature under the studied pressures. The study of universal anisotropy indices shows the significant anisotropic nature of CaPd2P2. The melting temperature increases with the applied pressure, which benefits the suitability of the higher-temperature applications of CaPd2P2. The CaPd2P2 compound reveals prominent optical absorption of UV radiation and becomes maximum near about 10 eV of photon energy. Almost a flat and significant amount of reflectivity is noticed between 9 and 18 eV of photon energy, and then the reflectivity spectra shift to the higher energy with the increasing applied pressure. The DOS analysis reveals that the Pd–P antibonding is largely responsible for the emergence of superconductivity in CaPd2P2, which justifies the previous reports. The value of DOS does not change significantly with the applied pressure. The increasing trend of the Debye temperature with pressure predicts that the superconducting transition temperature of the low-temperature superconductor CaPd2P2 might be increased with the applied pressure for a particular value of the electron–phonon coupling constant. This study concludes that applied pressure can be an efficient and clean thermodynamic approach to obtaining interesting physical properties of materials. The authors of this research work strongly believe that these interesting features of CaPd2P2 under pressure will attract enormous attention of the researchers to study the effects of pressure on superconducting materials both theoretically and experimentally.