Strain Effects on the Two-Dimensional Cr2N MXene: An Ab Initio Study.

Structural, electronic, and magnetic properties of two-dimensional Cr2N MXene under strain were studied. The uniaxial and biaxial strain was considered from -5 to 5%. Phonon dispersion was calculated; imaginary frequency was not found for both kinds of strain. Phonon density of states displays an interesting relation between strain and optical phonon gaps (OPGs), that it implies tunable thermal conductivity. When we apply biaxial tensile strain, the OPG increases; however, this is not appreciable under uniaxial strain. The electronic properties of the dynamically stable systems were investigated by calculating the band structure and electron localization function (ELF) along the (110) plane. The band structure showed a metallic behavior under compressive strain; nevertheless, under tensile strain, the system has a little indirect band gap of 0.16 eV. By analyzing, the ELF interactions between Cr-N are determined to be a weaker covalent bonding Cr2N under tensile strain. On the other hand, if the Cr atoms reduce or increase their self-distance, the magnetization alignment changes, also the magnetic anisotropy energy displays out-of-plane spin alignment. These properties extend the potential applications of Cr2N in the spintronic area as long as they can be grown on substrates with high lattice mismatch, conserving their magnetic properties.

Introduction

Spintronics is one of the most active research fields. Contrasting conventional electronic devices which are performed by a charge carrier, the switch of a spin-governed device uses spin waves as information carriers or by the magnon–phonon effect, which can be much faster and with less power dissipation.[1−3]

Since the remarkable physical and chemical properties of graphene were explored,[4,5] other two-dimensional (2D) materials have attracted interest and attention because of their intrinsic properties[6−9] that are being actively sought to fabricate high-performance electronic devices. A great solution to reduce inefficiencies of graphene and quasi-graphene structures is the creation of graphene-based van der Waals (VdW) heterostructures by positioning graphene on top of other 2D materials.[10]

In spite of the research efforts in 2D semiconductors and optoelectronics materials, 2D magnetic materials remain still unexplored, due to the fact that most of the 2D materials already synthesized have been intrinsically nonmagnetic. However, experimental and theoretical studies in recent years reveal that magnetic properties can be controlled by introducing edge structures, doping, surface functionalization, or creating defects.[11−13] In this sense, 2D hexagonal CrN displays half-metal behavior with a possible ferromagnetic (FM) ordering when it is isolated[14] and preserves its properties as it happens in MoSe2 and MoS2 heterostructure.[15] Besides, strain engineering[16] is an important strategy for tuning the lattice and electronic structure of 2D materials, and there are different methods of inducing strain from the lattice mismatch, for example, the use of different substrates, such as flexible substrates, patterned substrates, and piezoelectric substrates, to the action of atomic force microscope tips and bubbles.[17]

MXenes are a new family of 2D transition-metal carbide/nitrides, discovered in 2011,[18] which are a family of layered hexagonal transition-metal carbides/nitrides with theoretically infinite lateral dimensions but atomically thin thickness.[19] The chemical formula is MXT2 (n = 1, 2, and 3), where M is an early transition-metal element, X is carbon or nitrogen, and T (T = OH, O, and F) is a surface functional group.[20] Since the first discovered Ti3C2T2 MXene, more than 70% of all MXene research has been focused on it.[21] MXenes had been predicted, and their physics and chemical properties were described by theoretical studies,[22] principally with intrinsic ferromagnetism.[23−25] The MXenes exhibit outstanding electronic, optical-mechanical, and thermal properties with versatile transition metal and surface chemistries.[26] Furthermore, they could be a promising candidate to be employed in heterostructures as metal electrodes, photodetectors, and in solar cell applications,[27−29] and due to the VdW interactions, they can be candidates for anodes in batteries.[30] In addition, when strain is applied on MXenes, for example WCrCO2, their electronic properties change to a semi metallic character with a dual narrow band gap.[31] The VdW heterostructure Mn2CFCl/MoSSe has the potential applications in spintronic devices due to its perpendicular magnetic anisotropy (PMA) that can be regulated by the biaxial strain and an external electric field.[32]

The nitride-based MXene possess an advantage in comparison with carbide MXenes due to a higher electronic conductivity[30,33] and magnetic moments,[34] so they could be suitable candidates for electrodes in electrochemical capacitors or metamaterials devices.[35,36] Moreover, a previous theoretical study had considered possible magnetic configurations where the most favorable for Cr2N pristine is the antiferromagnetic (AFM) order where the different Cr layers are antiparallel to each other and have metallic behavior.[37] Nevertheless, this MXene displays a FM ground state that acts a half-metallic when it is functionalized,[34,37] also the ground state above room temperature is stable, robust, and can be maintained under tensile strains up to 10%.[38] Subsequently, the electronic and magnetic properties could be tunable by applying compressive and tensile strain, such is the case for the MXene semiconductors[34] and in the MXenes that display magnetic anisotropy.[39]

Electronic and magnetic properties of Cr2N MXene could be tunable as a result of lattice parameter mismatch to build heterostructure or by deformation induction, as shown in 2D systems.[39,40] In this sense, we study the biaxial and uniaxial strain effect on Cr2N MXene pristine. The MXene is dynamically stable under compressive or tensile stress and keeps its metallic characteristics. Even if it preserves the AFM behavior, the magnetic spin polarization between Cr layers is different to pristine MXene unstrained, and the magnetic moment magnitude depends if it is under compressive or tensile strain, allowing it to be a good option for applications in 2D spintronics as contacts.

Computational Methods

The structural, electronic, and magnetic properties of the Cr2N MXene under tensile and compressive strain are investigated by spin-polarized first-principle calculations. Calculations were performed in the periodic density functional theory (DFT) framework, as implemented in the Vienna Ab initio Simulation Package,[41−73] that utilizes a plane wave basis set to represent electron states. The exchange–correlation energies were treated using the generalized gradient approximation with Perdew–Burke–Ernzerhof parametrization.[42] Because Cr is a transition metal with 3d orbitals, it exhibits high correlation electrons. Therefore, to treat the high correlated electrons, we use the Hubbard Correction (DFT + U) method,[44] employing the methodology proposed by Dudarev et al.[43] We employed a value of U = 3 eV to treat the Cr-3d orbitals as in previous reports.[46] The electronic states were expanded using the projector-augmented wave basis[45,74] with an energy cutoff of 460 eV. The Cr2N MXenes were simulated with the supercell method with a vacuum space of 15 Å. To study the electronic and magnetic properties, a monolayer of the Cr2N supercell with 2 × 2 periodicity was constructed, and we consider different magnetic configurations without any constraints. To achieve convergence, all the force components must be less than 0.01 eV/Å and total energy differences less than 1 × 10–9 eV. The Brillouin zone was sampled using a Monkhorst–Pack mesh[47] of 15 × 15 × 1 k points. Phonon dispersions were obtained using the finite-differences method[48] combined with the Phonopy code.[49] By using 2 × 2 periodicity with integration of 7 × 7 × 1, the dynamical stability of the system has been achieved. Furthermore, the molecular dynamics simulations were performed by the CASTEP package[50] at 300 K, and a time step of 5 fs is set with 500 simulation steps.

Results and Discussion

The structure of MXene was built by removing the A-element group element atomic layer from their corresponding Cr2GaN MAX phase (mostly IIIA and IVA).[46,51] The unit cell includes three atoms, two chromium (Cr) and one nitrogen (N), which resides in the P3̅m1 space group. The Cr atoms are located at (1/3, 2/3, z) and (2/3, 1/3, −z) on the 2d Wyckoff sites; meanwhile, the N atom is located at (0, 0, 0) on the 1a Wyckoff site.[52][53] Then, the MXene Cr2N has a centered honeycomb (T) structure where the N atoms are in-between two layers of the hexagonal lattice of Cr atoms.[54] The interplanar distance is 1.14 Å, and the Cr–N bonds have a distance of 2.12 and 2.06 Å, for more details see Figure S1 in Supporting Information. Figure displays a top and side view of the crystal structure of the unstrained Cr2N MXene.

Figure 1

Top and side view of Cr2N MXene with (2 × 2) periodicity.

To study the strain effect on this MXene, biaxial (x–y) and uniaxial (y) strain (ε) was applied, see Figure . The strain is defined aswhere a0 and a are the lattice parameters of the unstrained and strained structures, respectively. The positive and negative values correspond to tensile and compressive strains, respectively, for a range from −5% ≤ ε ≤ 5% for each deformation.

Figure 2

Top and side view of Cr2N under biaxial and uniaxial strain.

To determine the dynamical stability, we calculate the phonon bands; results are shown in Figure . These phonon dispersions are plotted along the path Γ-M-K-Γ. It is worth to notice that non-negative frequencies are present for any deformation, meaning that the system is stable under biaxial and uniaxial strain in all the range applied. As reported for a similar crystal structure and chemical bonding M2C MXene,[55] the phonon dispersions have three acoustic modes; two of them exhibit a linear dispersion near Γ and correspond to in-plane rigid body motions. In contrast, the third acoustic mode corresponds to out-of-plane vibrations, and it has a quadratic dispersion close to Γ and lower energy in the rest of the spectrum, which is a common feature in covalent, VdW monolayer and multilayer 2D lattices[52,56,57] due to accuracy of the harmonic interatomic force constants.[58−60] Taking into account the crystal structure of the MXene, the optical modes at the zone center of the Brillouin zone can be classified with the following irreducible formula[61]where the E-symmetry modes (Eg and Eu) are doubly degenerate. The two Raman-(Eg + A1g) and IR (A2u + Eu) optical mode frequencies of MXene free and under stress or strained are listed in Table . Note that for uniaxial compressive and tensile strain, the Eg and A2u phonon bands unfold, 196.66 and 187.79 cm–1 for Eg while for Au2 are 442.84 and 438.78 cm–1, see Figure . This is due to the symmetry breaking, although the system is dynamically stable, as reported in similar MXenes.[61] The correspondence between the vibrational modes of Cr2N free and under compressive and tensile strain is determined by the direction of the vibrations and the nature of the contributing atoms, then for Cr atoms, the Raman-active modes are associated with in-plane and out-plane vibrations for Eg and A1g, respectively, as reported by Champagne.[52] The schematic displaced representations of the atoms are illustrated in Figure , where the atoms are displaced along x–y for Cr2N free-strain due to Eg intensity being higher than A1g, while under biaxial and uniaxial strain, the atoms change their out-plane z displacement because the phonon band intensity of A1g is comparable with Eg.

Figure 3

Phonon band structure and densities of states of unstrained Cr2N (upper part), under biaxial compressive and tensile strain (middle part), and under uniaxial compressive and tensile strain (bottom part).

Table 1

Vibrational Mode Frequencies of the Stable Cr2N MXenea

Raman modes				IR modes
P3̅m1 (164)	Eg		A1g	A2u		Eu
Cr2N unstrained	179.28		305.14	416.17		651.67
–5% biaxial strain	198.49		239.75	416.36		661.91
5% biaxial strain	203.61		275.72	594.77		502.81
–5% uniaxial strain	171.65	196.66	299.23	388.51	442.84	656.68
5% uniaxial strain	144.36	187.79	260.26	389.65	438.78	631.05

E modes are degenerate.

Figure 4

Atomic displacements of the vibration modes for Cr2N MXene unstrained and under biaxial or uniaxial compressive and tensile strain. The dot on the atom corresponds to vibration direction pointing into the plane, and the arrow corresponds to the in-plane vibration.

The highest peaks in energy in the phonon density of states (phonon DOS) correspond to N atom vibrations. Moreover, the first three optical branches in the phonon spectrum demonstrate lower frequencies close to the three acoustic phonon branches where it corresponds to the vibration of Cr atoms. Furthermore, the optical phonon gap (OPG) induced is summarized in Table . It is noteworthy that under uniaxial strain, the OPG decreases while under biaxial strain decreases and increases when applying compressive and tensile strain, respectively (for details, see Figures S2 and S3 in the Supporting Information). The existence of a phonon gap between optical phonons implies larger thermal conductivity[56] that could be engineered by strain.

Table 2

Optical Phonon Gap and Upper Limit Optical Branch for Cr2N Unstrained and under Strain

		biaxial strain		uniaxial strain
	Cr2N unstrained	–5%	5%	–5%	5%
optical phonon gap [cm–1]	109.08	59.38	167.79	48.20	91.23
upper limit optical branches [cm–1]	715.86	744.88	683.67	745.88	656.31

In addition, Table exhibits the maximum frequencies of the phonon spectrum that could be associated with the Debye temperature and describe the Debye stiffness of the system[56] due to the fact that it includes the optical phonon excitation resistance.[62] In this sense, Debye stiffness (being an important parameter to represent the resistance to overall phonon excitation[62]) of the Cr2N under strain is much lower than that of graphene, where the maximum optical frequency is around 1500 cm–1,[56] two times higher than the strained Cr2N MXene.

To analyze the thermal stability of unstrained and strained Cr2N monolayer, Figure displays the ab initio molecular dynamics (AIMD) simulation results that have been carried out at 300 K. Herein, a time step of 5 fs is set with 500 simulation steps (total simulation time of 2.5 ps). Note that no structural destruction occurs despite its constituent atoms vibrate around their equilibrium positions, suggesting good thermal stability of the studied 2D materials in both unstrained and strained states.

Figure 5

Fluctuation of temperature as a function of molecular dynamics simulation steps at 300 K of Cr2N monolayer at (a) biaxial compression of −5%, (b) biaxial tension of +5%, (c) unstrained state, (d) uniaxial compression of −5%, and (e) uniaxial compression of +5%.

Regarding the magnetic properties, Figure a,b shows the different magnetic configuration of the 2D unstrained Cr2N MXene and the magnetic anisotropy at the high symmetry hexagonal lattice, respectively. The Cr atoms at different polarizations are marked with yellow and red balls for spin up and spin down, respectively. The FM and different AFM configurations were considered in the calculations. Since the Cr2N has two Cr monolayers on top and bottom, the spin in the different Cr layers was polarized parallel to each other (FM, AFM2, and AFM4), or the Cr layers are antiparallel (AFM1, AFM3, and AFM5).[37] The magnetic anisotropy is calculated by the spin–orbit coupling for magnetic alignments along the x- and z-axes, as shown in Figure b. Magnetic alignments are set without any constraint.

Figure 6

(a) Possible magnetic polarization in Cr2N MXene; yellow and red balls correspond to spin up and spin down, respectively, and (b) schematic of the Cr2N MXene structure highlighting high-symmetry axes, in-plane are (100), (110), and (010), and out-of-plane are (001) and (111) directions.

The relative energies per primitive cell of the FM, AFM1, AFM2, AFM3, AFM4, and AFM5 unstrained MXenes are 1.42, 0.93, 0.43, 0, 5.76 × 10–5, and 0.43 eV, respectively. Note that Cr2N unstrained has an AFM3 ground state, as described in previous reports,[37] also we consider different values of U to treat the highly correlated electrons from Cr, and our results show that U = 3 eV reproduces the results previously published (for more details, see Table S1 of Supporting Information). Table summarizes the relative energies for the six magnetic configurations when applying compressive and tensile strain. For biaxial strain, the AFM4 is the most favorable configuration under compressive deformation; nevertheless, under tensile strain in the interval 1% < ε ≤ 3%, the AFM3 is the most favorable, and for larger values of strain, the system switches to AFM4 as the most favorable configuration. Meanwhile for uniaxial strain, the AFM4 is the most favorable configuration under compressive deformation in the interval −5% < ε ≤ −3% and preserve the AFM3 configuration only from −2% < ε ≤ 0%, although for a tensile strain, the AFM4 is the most favorable characteristic.

Table 3

Relative Energies (meV) of Magnetic Configurations of the Cr2N MXene Unstrained and Biaxial and Uniaxial Strained

	biaxial strain						uniaxial strain
% strain	FM	AFM 1	AFM 2	AFM3	AFM4	AFM 5	FM	AFM 1	AFM 2	AFM 3	AFM 4	AFM 5
–5	1783.77	1483.09	261.27	0.22	0.00	261.16	1598.39	1120.01	401.61	56.42	0.00	324.68
–4	1677.83	1332.92	288.59	0.34	0.00	288.24	1541.35	889.68	384.35	27.04	0.00	340.87
–3	1583.58	1199.23	317.49	0.03	0.00	317.19	1496.07	954.01	379.40	6.32	0.00	361.24
–2	1511.61	1089.76	349.68	0.02	0.00	349.52	1465.12	866.50	391.28	0.00	6.23	388.16
–1	1455.77	999.86	386.98	0.01	0.00	387.16	1441.17	799.23	411.30	0.00	10.91	414.51
0	1415.83	930.76	430.00	0.00	0.06	429.98	1415.83	930.76	430.00	0.00	0.06	429.98
1	1386.60	880.19	477.17	0.00	0.07	477.14	1395.83	896.76	455.05	2.71	0.00	447.24
2	1345.71	848.34	527.03	0.00	0.18	527.14	1385.53	872.73	490.91	20.52	0.00	468.43
3	1291.70	836.33	584.41	0.00	0.01	584.55	1375.33	847.45	531.54	45.00	0.00	490.50
4	1240.79	834.80	642.87	0.03	0.00	642.88	1359.91	819.48	575.53	76.33	0.00	514.32
5	1201.22	834.84	704.04	0.04	0.00	704.03	1339.38	787.40	621.93	113.01	0.00	538.98

Moreover, from the magnetic anisotropy energy (MAE) performed for the upper and lower strain limits, the results exhibit an out-of-plane spin alignment for unstrained and under uniaxial strain. Regarding MXene under biaxial tensile strain, it preserves the same spin alignment as unstrained Cr2N; nevertheless, under compressive strain, the in-plane alignment is the most stable. The out-of-plane alignment is 0.05 meV less stable. Table S2 of Supporting Information displays the MAE for all deformation percentages. Note that the spin orientation changes due to the increment or decrement distance between the Cr layer (see Figure S4). This effect gains importance when applying biaxial compressive strain.

With this in mind, it can be seen that the magnetic configuration depends on the Cr–N bond length. Figure a,b exhibits the bond distance of Cr2N under biaxial and uniaxial strain, respectively. Three kinds of bond lengths named as Cr–N1, Cr–N4, and Cr–N2 (black, red, and green dots-lines, respectively) have been plotted that correspond with the [−210], [−120], and [110] directions, respectively. Unstrained Cr2N MXene displays AFM3 configuration with Cr–N4 > Cr–N1 and Cr–N1, and the Cr–N1 is equal to Cr–N2. After applying compressive or tensile strain, the bond lengths display a linear decrement or increment, respectively.

Figure 7

Bond length and the most stable magnetic configuration of the Cr2N MXene unstrained, (a) under biaxial and (b) under uniaxial strained.

Concerning with Figure a, when the Cr2N is under biaxial −5% strain, the AFM4 configuration is favorable because of keeping the relation Cr–N2 > Cr–N1 > Cr–N4 where the Cr–N2 has a slope of 0.122 (green dots) and 0.105 for Cr–N1 and Cr–N4 (black and red dots, respectively). The magnetic configuration switch to AFM3 in the range from 1 to 3% strain with a relation Cr–N4 > Cr–N1 and Cr–N2; the Cr–N4 bond slope is 0.098 (red dots) and 0.107 for Cr–N2 and Cr–N1 (green and black dots, respectively), persevering the relation of Cr2N unstrained. Although for 4 and 5% strain, the system prefers the AFM4 behavior, where Cr–N2 > Cr–N4 > Cr–N1 and the slope for Cr–N2, Cr–N1, and Cr–N4 bonds are of 0.10, 0.134, and 0.119, respectively.

In the meantime, under larger values of uniaxial compressive strain shows AFM4 due to Cr–N2 > Cr–N4 > Cr–N1 where the Cr–N2, Cr–N4, and Cr–N1 have a slope of 0.060, 0.022, and 0.071 (green, red, and black dots, respectively), see Figure b. Nevertheless, under −2 and −3% of compressive strain, the system switches to AFM3 configurations because the bond relations are Cr–N4 > Cr–N2 > Cr–N1 with a slope of 0.022, 0.060, and 0.071 for Cr–N4, Cr–N2, and Cr–N1, respectively (red, green, and black dots, respectively). Under tensile strain, the system has AFM4 characteristics due to Cr–N2 > Cr–N1 > Cr–N4, where Cr–N2 and Cr–N1 have a slope of 0.045 and 0.122, respectively (green and black dots, respectively) but for Cr–N4 displays a slope of 0.006 (red dots).

Regarding variation of the Cr magnetic moment magnitude, it maintains a dependence with the Cr layer distance, see Figure . In the other words, under biaxial and uniaxial compressive strain, the Cr magnetic moment magnitude decreases to ±3.12 μβ and ±3.18 μβ, respectively, in comparison with unstrained MXene ±3.23 μβ. However, under biaxial and uniaxial tensile strain, the magnitude increases to ±3.30 μβ and ±3.27 μβ, respectively. It could be associated with the inverse magnetostriction effect, where the magnetic properties change after applying mechanical deformation, as shown in some 2D systems.[63−65] This could be further used to combine MXene with other 2D materials and produce VdW heterostructures.[55]

Figure 8

Cr and N magnetic moment of the Cr2N unstrained and biaxial and uniaxial compressive/tensile strain.

Note that the magnetic moment magnitude displays a major increment or decrement when the Cr2N is under compressive and tensile biaxial strain because the distance between Cr layer tends to be larger than that under uniaxial strain, as shown in Figure S4 of Supporting Information. Therefore, as the system is strained, the magnetic moment of Cr enhances, as shown in Cr2NO2.[38] Furthermore, the N atoms have induced magnetic moment either under uniaxial or biaxial strain of the order of ±0.12 μβ.

Based on the stable magnetic configurations after applying compressive or tensile strain, the charge transfer was studied by the electron localization function (ELF) along the (001) plane. Figure shows a Cr2N MXene top view of the ELF, where the first, second, and third columns from left to right correspond to compressive strain, strain-free, and tensile strain, respectively.

Figure 9

ELF results of the Cr2N MXene under biaxial/uniaxial compressive strain, unstrained, and under biaxial/uniaxial tensile strain.

ELF analysis allows a direct observation of the change of chemical bonding, the regions close to the unity (red areas) contain many localized electrons, which indicates a region around a nucleus or in a very strong covalent bonding condition. Values close to zero (blue areas) represent the regions with low electron density, and the values close to 0.5 (green areas) correspond to a uniform electron gas where the bonding might have a metallic character.[66,67]

It can be noted that for unstrained Cr2N, the Cr atom electrons are transferred to N atoms, then the electron concentration is located around N atoms, characteristics of ionic bonds.[68−70] Besides, after applying biaxial compressive strain, N atoms preserve the electron distribution. Nevertheless, under uniaxial compressive strain, the electron dispersion of N atoms is not uniform, the higher electron concentration is oriented in the direction to Cr atoms that the total electron transferred; meanwhile, the region with values close to 0.5 is oriented toward Cr atoms with a low electron density. Instead, electron clouds rise around Cr atoms that could propitiate a covalent bond with N atoms when the MXene is under biaxial and uniaxial tensile strain; this behavior is discussed with the band structure hereinafter.

To explore electronic properties, the band structure was calculated based on the stable magnetic configurations after applying compressive or tensile strain. The top and bottom graphs, as shown in Figure , correspond for upper and lower limits of biaxial and uniaxial strain, respectively. The compressive and tensile strain upper limits where the Cr2N is dynamically stable in the interval from −5% < ε < 5%, strains were plotted. In all plots, the Fermi level is the energy reference. The Cr2N MXene free-strain has a metallic behavior, which is preserved under compressive strain. Nevertheless, under tensile strain, it presents an indirect band gap, in which the valence band maximum coincides along the G-M direction and conduction band minimum locates at K-point. The band gap is of 0.16 and 0.05 eV for biaxial and uniaxial tensile strain, respectively. As shown under tensile strain ELF, the increment of electron density around Cr atoms could cause a covalent bonding. Band structures for all compressive and tensile strain percentages can be found in Figures S5 and S6 in Supporting Information.

Figure 10

Band structure of MXene Cr2N under biaxial strain, (a) compressive, (b) without strain, and (c) tensile strain. The Cr2N with uniaxial strain, (d) compressive strain, (e) without strain, and (f) tensile strain.

As semiconductor MXenes, where the band gap is controllable with respect to various biaxial strains,[71] the Cr2N MXene displays a similar behavior where it preserves AFM characteristics. Note that in this case, we do not consider another band gap correction due to this behavior, which is not experimentally reported yet, we only consider the appropriate Hubbard parameter,[37].[38]

Conclusions

We have performed a comprehensive study of the effect of biaxial and uniaxial stress on the structural, electronic, and magnetic properties of Cr2N MXene through first-principles simulation. The OPG of the MXene can be continuously tuned via external compressive or tensile strain, preserving the structural stability. After applying an appropriate strain, the MXene experiments a magnetic transition from AFM3 to AFM4 configurations. The MAE displays that the unstrained MXene has an out-of-plane spin alignment and in-plane under biaxial compressive strain where the magnetic moment magnitude of the Cr atoms decreases or increases if the MXene is under compressive or tensile strain. Furthermore, the band structure graphs indicate that the MXenes under compressive strain preserve the metallic property; nevertheless, under tensile strain, it has a little indirect band gap. These properties extend the potential applications in the spintronics area as long as they can be grown on substrates with high lattice mismatch or employed with other 2D materials and produce VdW heterostructures, owing to the tunable electronic and the Cr spin orientation by the compressive or tensile strain applied.