Understanding the correlation between the electronic and magnetic properties of materials is a crucial step to functionalize or modulate their properties. However, it is not straightforward to electrically characterize magnetic insulators, especially large-bandgap materials, due to their high resistivity. Here, we successfully performed electrical measurements of a two-dimensional (2D) antiferromagnetic insulator, van der Waals-layered MnPS3, by accounting for the vertical graphene/MnPS3/graphene heterostructure. Antiferromagnetic transition is observed by the variance in electrical resistance from the paramagnetic to antiferromagnetic transition near ∼78 K in the vertically stacked heterostructure devices, which is consistent with the magnetic moment measurement. This opens an opportunity for modulating the magnetic transition of 2D van der Waals materials via an electrical gate or surface functionalization.

It has been predicted theoretically that the long-range two-dimensional (2D) magnetic order is unstable for isotropic spin systems.1 However, it does not interfere with the search for anisotropic 2D magnetic orders. Recently, the 2D van der Waals (vdW)-layered magnetic materials of one-atom-thick monolayers are emerging with various ferromagnetic material families, such as Cr2Ge2Te6,2–4 CrI3,5–11 Fe3GeTe2,12–14 CrSiTe3,15–17 VSe2,18,19 V-doped WSe2,20 and so on. It gives rise to opportunities to control the magnetic properties via electrical gating,8,11,14 external magnetic field,2,7 proximity effects,21,22 as well as the attempt of several spintronic devices.9,23,24

While there has been immense interest in 2D vdW-layered ferromagnetic materials,25–28 2D vdW-layered antiferromagnetic materials are also attractive, not only for their rich physics29–32 but also for their potential applications for spintronic devices.33–36 To date, the main 2D vdW antiferromagnetic families are based on the compounds of transition metals, phosphorus, and chalcogenides (MPChs) such as the MPS329,37,38 and MPS4 families.39,40 FePS3, NiPS3, and MnPS3 exhibit antiferromagnetic ordering at low temperatures in a bulk form with the corresponding Ising, XYZ, and Heisenberg types.37 Similar to the 2D vdW ferromagnetism, the antiferromagnetic order has been proven to exist at a single-atom-thick layer in FePS3.41 Interestingly, the antiferromagnetic insulator phase in bulk FePS3 can be melted and transformed into the superconducting phase under high pressure, providing similarity to the high-Tc cuprate phase diagram.42,43

Magnetic phase transition has been revealed by direct measurement methods, such as neutron scattering and vibrating-sample magnetometer (VSM).37,44 The transition can also be detected indirectly by using vibration spectroscopy, owing to the strong spin-phonon coupling when the magnetic phase appears.41,45,46 In addition, an abnormal variation in resistance with temperature appears at the magnetic transition state, which has been observed in both ferromagnetic and antiferromagnetic metals.13 Nevertheless, this observation is not clarified in magnetic insulators, especially the MPS3 family, due to their high resistivity and contact resistance.47,48 Here, we report the observation of antiferromagnetic phase transition for 2D vdW-layered MnPS3 via electrical resistance measurement in an h-BN/Gr/MnPS3/Gr heterostructure. The device is constructed vertically by using top and bottom multilayer graphene sandwiched by a MnPS3 flake to overcome its low conductivity. The resistance slope clearly exhibits a phase transition, which is consistent with the magnetic susceptibility measurement. Our work demonstrates that the vdW-layered antiferromagnetic insulators can be robustly observed by means of electrical measurement under gate control as well as surface chemical doping.

A typical MnPS3 single crystal, on the order of several millimeters, was synthesized by the chemical vapor transport method [Fig. 1(a)]. The detailed fabrication method for crystal growth is described in Sec. IV. Three dominant peaks appear at 13.7°, 27.5°, and 56.8° from X-ray diffraction (XRD) patterns, corresponding to the (001), (002), and (004) planes, which is highly consistent with the reference pattern (PDF#01-078-0495). The high-intensity XRD peaks along the c axis indicate a high-quality single crystal of MnPS3 [Fig. 1(b)]. Figure 1(c) shows the Raman spectrum of bulk MnPS3 at room temperature with an exposure time of 2 min and a laser power of 500 µW. Two dominant Raman modes, (Ag, Bg) and (Ag), are present near 273.9 and 383.3 cm−1, respectively. Moreover, several Raman peaks appear at 155.2, 223.6, 246.3, 566.8, and 579.7 cm−1 with smaller intensities, which are congruent with the vibration modes in previous works.48–50 

FIG. 1.

Synthesized single-crystal MnPS3. (a) Optical image of single-crystal MnPS3. (b) XRD patterns of single-crystal MnPS3 (top) and reference (bottom). (c) Raman spectrum of bulk MnPS3 by 514 nm laser excitation at 300 K. (d) X-ray photoelectron spectra and peak deconvolution for the elements (P 2p, S 2p, and Mn 2p) of single-crystal MnPS3.

FIG. 1.

Synthesized single-crystal MnPS3. (a) Optical image of single-crystal MnPS3. (b) XRD patterns of single-crystal MnPS3 (top) and reference (bottom). (c) Raman spectrum of bulk MnPS3 by 514 nm laser excitation at 300 K. (d) X-ray photoelectron spectra and peak deconvolution for the elements (P 2p, S 2p, and Mn 2p) of single-crystal MnPS3.

Close modal

The chemical composition of the MnPS3 crystal was identified by three atoms of P, S, and Mn via photoelectron spectroscopy (XPS) [Fig. 1(d)]. The 2p peaks from the P atom can be assigned to 2p1/2 near 132.8 eV and 2p3/2 near 132 eV (left panel), and similarly, S 2p peaks are assigned to 2p1/2 near 163.5 eV and 2p3/2 near 162.3 eV (middle panel). In contrast to the single oxidation state of P and S, the oxidation state of Mn appeared in Mn2+ and Mn3+. The XPS spectrum of Mn displays the presence of 2p1/2 and 2p3/2 peaks, which can be identified at, respectively, 653.5 and 652.3 eV for Mn3+ and Mn2+, and 642.1 and 640.8 eV for Mn3+ and Mn2+ states (right panel). In addition, their satellite peaks at ∼645.9 and 659.3 eV also emerged due to the interaction of 3p-3d at the optical absorption edge or Mn vacancies at the surface.51 The atomic ratio of Mn, P, and S is 16.07:22.31:61.62 from the XPS measurement, which is quite different from the expected value (1:1:3). While the P:S ratio is nearly 1:3, the amount of Mn is a little less than 1, indicating Mn vacancies in our synthesized MnPS3. This may also be correlated with the appearance of two oxidation states of Mn. Nevertheless, such defects do not strongly modify the magnetic transition temperature of MnPS3, which appears at 78 K in the magnetic measurement later.

To study the electrical properties of MnPS3, we first fabricated the lateral field-effect transistor configuration (see Fig. S1). The current is less than 1 pA under applied gate voltages from −30 to 30 V. The source-drain current is also too low to manifest sensible current flow. Such a high resistance of the MnPS3 sample was also observed in other studies.47,48 It is worth noting that the lateral devices of MnPS3 can often operate under high doping concentration via a liquid gate.48 However, such a highly doped regime may modulate the intrinsic properties of MnPS3. Therefore, development of the proper device configurations is required to characterize the intrinsic magnetic properties of MnPS3.

Figure 2(a) illustrates the schematic structure of a vertical h-BN/Gr/MnPS3/Gr device with a multilayer MnPS3 thickness. First, h-BN thin film was deposited on SiO2/Si by the mechanical exfoliation method as a clean substrate. Then, the exfoliated bottom graphene, MnPS3, and top graphene layers were successively deposited on the h-BN substrate via a dry transfer technique.52 Subsequently, the metal contact electrode of Cr/Au (10/50 nm) was deposited on the bottom and top graphene layers by the e-beam/thermal evaporation method, followed by e-beam patterning. Figures 2(b) and 2(c) show the optical image of the vertical device and its atomic force microscopy (AFM) topographic image, respectively. The bubbles caused by trapped ambient gas or moisture are inevitable due to the artificial transfer method for mechanical exfoliation. The inset in Fig. 2(c) indicates the height profile of the MnPS3 flake, with the thickness estimated as approximately 5.6 nm.

FIG. 2.

Device structure and interlayer resistance. (a) Schematic structure and (b) optical image of vertical device (h-BN/Gr/MnPS3/Gr). (c) AFM image corresponding to the device structure. The inset shows the thickness of multilayer MnPS3.

FIG. 2.

Device structure and interlayer resistance. (a) Schematic structure and (b) optical image of vertical device (h-BN/Gr/MnPS3/Gr). (c) AFM image corresponding to the device structure. The inset shows the thickness of multilayer MnPS3.

Close modal

The phase transition from antiferromagnetism to paramagnetism with temperature variance was observed by measuring the magnetic susceptibility of the sample (see Sec. IV). The in-plane and out-of-plane magnetic susceptibilities of multilayer MnPS3 were measured as a function of temperature (Fig. 3, top and bottom panels). The similarity of the zero-field-cooling (ZFC) and field-cooling (FC) curves explains the well-ordered magnetic states. The derivative of out-of-plane magnetic susceptibility clearly visualizes the phase transition from paramagnetic at high temperatures to antiferromagnetic at low temperatures at approximately 78 K. A similar phase transition was observed for in-plane magnetic susceptibility. Therefore, the antiferromagnetic phase transition of MnPS3 is clearly consistent with other reports.48,53 Interestingly, below the Néel temperature, the out-of-plane susceptibility is suppressed rapidly at 0.1 T, which is contrasted with the further rise of in-plane susceptibility. This special characteristic normally occurs in canted antiferromagnetic systems, where the spin orientation can be modulated by a high external magnetic field.54,55

FIG. 3.

Magnetic susceptibility of bulk MnPS3 as a function of temperature for out-of-plane and in-plane directions at zero field cooling (ZFC) and field cooling (FC).

FIG. 3.

Magnetic susceptibility of bulk MnPS3 as a function of temperature for out-of-plane and in-plane directions at zero field cooling (ZFC) and field cooling (FC).

Close modal

We now demonstrate that the magnetic phase transition with temperature can be identified by simply measuring the resistance of vertically stacked devices in which the MnPS3 layer is sandwiched between the top and bottom graphene layers as the source and drain [see Fig. 2(a)]. The MnPS3 layer is insulating and usually inaccessible to measure the current in the long in-plane channel due to its high resistance. In our case, however, the resistance of the vertically stacked device shrinks as the temperature increases, indicating semiconducting behavior (Fig. 4). An ultrathin layer of a few nanometers and quantum tunneling via the vdW gap in the vertical direction are the keys to the reduced resistance. Interestingly, the variation in resistance with temperature reveals a maximum value (minimum negative), which is distinct near 78 K. This critical temperature is coincident to the paramagnetic to antiferromagnetic transition in the magnetic moment curve in Fig. 3. This implies that the Néel temperature of the antiferromagnetic transition can be detected by a direct method via resistance measurement using the vertical device. The change in the band structure between the no-spin and antiferromagnetic states could be the origin of the resistance change from the antiferromagnetic semiconducting state to the paramagnetic metallic state (Figs. S2–S4). In addition, the possibility of contributing to spin-phonon coupling and electron-phonon coupling cannot be excluded.

FIG. 4.

Electrical resistance of vertical device (h-BN/Gr/MnPS3/Gr) (left axis) and its derivative (right axis) as a function of temperature.

FIG. 4.

Electrical resistance of vertical device (h-BN/Gr/MnPS3/Gr) (left axis) and its derivative (right axis) as a function of temperature.

Close modal

We have observed a strong correlation between the electrical and magnetic properties in MnPS3. The change in resistance of the thin MnPS3 flake with temperature was characterized by a vertical h-BN/Gr/MnPS3/Gr device, which reveals the paramagnetic to antiferromagnetic transition of MnPS3 near 78 K. This opens opportunities to study the magnetic phase transition of antiferromagnetic insulators by means of the vertical electrical transport probes in 2D vdW-heterostructure layered materials.

A stoichiometric amount of high-purity manganese, red phosphorus, sulfur (mole ratio Mn:P:S = 1:1:3, total amount ∼2 g), and iodine (∼20 mg) were mixed together and sealed in a quartz glass ampule under high vacuum (below 5 × 10−3 Pa), then kept in a two-zone furnace (750 − 650 °C). After 10 days of heating, the ampule was cooled to room temperature and the single-crystal MnPS3 was collected from the lower-temperature zone.

The multilayer h-BN flake was mechanically exfoliated from bulk materials (2D semiconductors, USA) onto SiO2 (300 nm)/Si wafers. The multilayer graphene and MnPS3 flakes were mechanically exfoliated from bulk materials on polymethyl methacrylate (PMMA) and polyvinyl alcohol (PVA)-coated SiO2 (300 nm)/Si wafers. To fabricate the bottom graphene layer, the multilayer graphene flake on the PPMA layer was transferred on the top of the multilayer h-BN flake on SiO2 (300 nm)/Si wafers via a dry transfer technique. The PMMA layer was removed by acetone and then rinsed with isopropyl alcohol. The multilayer MnPS3 and other multilayer graphene flakes were successively transferred on the bottom graphene layer after the above transfer process. The electrodes were fabricated using an electron beam (e-beam) lithography method. The PMMA e-beam masks for the electrodes were patterned on the h-BN/GrB/MnPS3/GrT heterostructure flake. Finally, the electrode metals of Cr/Au (10/50 nm) were deposited using the e-beam/thermal evaporation methods, and lift-off was conducted in acetone.

The topography of the sample was examined using AFM (E-sweep/Nano Navi) in noncontact mode. An optical micrograph for the bright-field mode was obtained by an optical microscope (100X, 0.9 NA, ZEISS, Axio Imager 2). Raman spectroscopy was measured under ambient conditions by using a laboratory-made confocal microscope system with 514-nm laser excitation, an objective lens (a numerical aperture of 0.95), and a laser power of 500 µW. The Raman signals were recorded with a spectrometer and a cooled charge-coupled device camera. The crystallographic structure analysis was carried out by employing an X-ray diffractometer (Rigaku, Smart Lab, Cu Kα radiation at 1.5418 Å, 45 kV, and 200 mA). X-ray photoelectron spectroscopy was examined by using an instrument (ESCA2000, VG Microtech, England) with an Al-Kα radiation source (1486.6 eV).

All electrical measurements were performed with a Keithley 4200 Semiconductor Analyzer inside Quantum Design PPMS.

The magnetic measurements were performed in Quantum Design PPMS with a vibrational sample magnetometer (VSM) by increasing the magnetic field to 9 T. First, the sample at room temperature was cooled to a low temperature (2 K) without a magnetic field. The susceptibility of the sample was measured from low temperatures to 350 K with a field of 0.1 T, called zero field cooling (ZFC). The sample was then cooled with a magnetic field to low temperatures again, and the susceptibility was measured from low temperatures to 350 K with the same magnetic field, called field cooling (FC). The in-plane and out-of-plane susceptibilities were each measured independently.

See the supplementary material for the lateral field-effect transistor devices and details of density functional theory calculation of the electronic band structure of MnPS3.

This work was supported by the Institute for Basic Science of Korea (Grant No. IBS-R011-D1) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant No. 2018R1D1A1A02046206). The computational support was provided by the Korea Institute of Science and Technology Information (KISTI) under Grant No. KSC-2016-C3-0042.

1.
N. D.
Mermin
and
H.
Wagner
, “
Absence of ferromagnetism or antiferromagnetism in one- or two-dimensional isotropic Heisenberg models
,”
Phys. Rev. Lett.
17
,
1133
1136
(
1966
).
2.
C.
Gong
 et al, “
Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals
,”
Nature
546
,
265
269
(
2017
).
3.
M.
Mogi
 et al, “
Ferromagnetic insulator Cr2Ge2Te6 thin films with perpendicular remanence
,”
APL Mater.
6
,
091104
(
2018
).
4.
Z.
Hao
 et al, “
Atomic scale electronic structure of the ferromagnetic semiconductor Cr2Ge2Te6
,”
Sci. Bull.
63
,
825
830
(
2018
).
5.
M. A.
McGuire
,
H.
Dixit
,
V. R.
Cooper
, and
B. C.
Sales
, “
Coupling of crystal structure and magnetism in the layered, ferromagnetic insulator CrI3
,”
Chem. Mater.
27
,
612
620
(
2015
).
6.
J. L.
Lado
 et al, “
On the origin of magnetic anisotropy in two dimensional CrI3
,”
2D Mater.
4
,
035002
(
2017
).
7.
B.
Huang
 et al, “
Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit
,”
Nature
546
,
270
273
(
2017
).
8.
S.
Jiang
 et al, “
Controlling magnetism in 2D CrI3 by electrostatic doping
,”
Nat. Nanotechnol.
13
,
549
553
(
2018
).
9.
D. R.
Klein
 et al, “
Probing magnetism in 2D van der Waals crystalline insulators via electron tunneling
,”
Science
360
1218
1222
(
2018
).
10.
P.
Jiang
,
L.
Li
,
Z.
Liao
,
Y. X.
Zhao
, and
Z.
Zhong
, “
Spin direction-controlled electronic band structure in two-dimensional ferromagnetic CrI3
,”
Nano Lett.
18
,
3844
3849
(
2018
).
11.
S.
Jiang
 et al, “
Electric-field switching of two-dimensional van der Waals magnets
,”
Nat. Mater.
17
,
406
410
(
2018
).
12.
Q.
Li
 et al, “
Patterning-induced ferromagnetism of Fe3GeTe2 van der Waals materials beyond room temperature
,”
Nano Lett.
18
,
5974
5980
(
2018
).
13.
Z.
Fei
 et al, “
Two-dimensional itinerant ferromagnetism in atomically thin Fe3GeTe2
,”
Nat. Mater.
17
,
778
782
(
2018
).
14.
Y.
Deng
 et al, “
Gate-tunable room-temperature ferromagnetism in two-dimensional Fe3GeTe2
,”
Nature
563
,
94
99
(
2018
).
15.
T. J.
Williams
 et al, “
Magnetic correlations in the quasi-two-dimensional semiconducting ferromagnet CrSiTe3
,”
Phys. Rev. B
92
,
144404
(
2015
).
16.
M. W.
Lin
 et al, “
Ultrathin nanosheets of CrSiTe3: A semiconducting two-dimensional ferromagnetic material
,”
J. Mater. Chem. C
4
,
315
322
(
2016
).
17.
S.
Wu
 et al, “
The direct observation of ferromagnetic domain of single crystal CrSiTe3
,”
AIP Adv.
8
,
055016
(
2018
).
18.
M.
Bonilla
 et al, “
Strong room-temperature ferromagnetism in VSe2 monolayers on van der Waals substrates
,”
Nat. Nanotechnol.
13
,
289
293
(
2018
).
19.
G. H.
Han
 et al, “
Van der Waals metallic transition metal dichalcogenides
,”
Chem. Rev.
118
,
6297
6336
(
2018
).
20.
S. J.
Yun
 et al, “
Room-temperature ferromagnetism in monolayer WSe2 semiconductor via vanadium dopant
,” e-print arXiv:1806.06479 (
2018
), pp.
1
10
.
21.
D.
Zhong
 et al, “
Van der Waals engineering of ferromagnetic semiconductor heterostructures for spin and valleytronics
,”
Sci. Adv.
3
,
e1603113
(
2017
).
22.
K. L.
Seyler
 et al, “
Valley manipulation by optically tuning the magnetic proximity effect in WSe2/CrI3 heterostructures
,”
Nano Lett.
18
,
3823
3828
(
2018
).
23.
T.
Song
 et al, “
Giant tunneling magnetoresistance in spin-filter van der Waals heterostructures
,”
Science
360
,
1214
1218
(
2018
).
24.
H. H.
Kim
 et al, “
One million percent tunnel magnetoresistance in a magnetic van der Waals heterostructure
,”
Nano Lett.
18
,
4885
4890
(
2018
).
25.
C.
Gong
and
X.
Zhang
, “
Two-dimensional magnetic crystals and emergent heterostructure devices
,”
Science
363
,
eaav4450
(
2019
).
26.
M.
Gibertini
 et al, “
Magnetic 2D materials and heterostructures
,”
Nat. Nanotechnol.
14
,
408
419
(
2019
).
27.
H.
Li
 et al, “
Intrinsic van der Waals magnetic materials from bulk to the 2D limit: New Frontiers of spintronics
,”
Adv. Mater.
31
,
1900065
(
2019
).
28.
D. L.
Cortie
 et al, “
Two-dimensional magnets: Forgotten history and recent progress towards spintronic applications
,”
Adv. Funct. Mater.
1901414
(
2019
).
29.
R.
Brec
, “
Review on structural and chemical properties of transition metal phosphorous trisulfides MPS3
,”
Solid State Ionics
22
,
3
30
(
1986
).
30.
M. A.
Susner
 et al, “
Metal thio- and selenophosphates as multifunctional van der Waals layered materials
,”
Adv. Mater.
29
,
1602852
(
2017
).
31.
K. S.
Burch
,
D.
Mandrus
, and
J. G.
Park
, “
Magnetism in two-dimensional van der Waals materials
,”
Nature
563
,
47
52
(
2018
).
32.
F.
Wang
 et al, “
New frontiers on van der Waals layered metal phosphorous trichalcogenides
,”
Adv. Funct. Mater.
28
,
1802151
(
2018
).
33.
V.
Baltz
 et al, “
Antiferromagnetic spintronics
,”
Rev. Mod. Phys.
90
,
015005
(
2018
).
34.
L.
Hao
 et al, “
Giant magnetic response of a two-dimensional antiferromagnet
,”
Nat. Phys.
14
,
806
810
(
2018
).
35.
W.
Jin
 et al, “
Raman fingerprint of two terahertz spin wave branches in a two-dimensional honeycomb Ising ferromagnet
,”
Nat. Commun.
9
,
5122
(
2018
).
36.
S.-J.
Gong
 et al, “
Electrically induced 2D half-metallic antiferromagnets and spin field effect transistors
,”
Proc. Natl. Acad. Sci. U. S. A.
115
,
8511
8516
(
2018
).
37.
P. A.
Joy
and
S.
Vasudevan
, “
Magnetism in the layered transition-metal thiophosphates MPS3 (M = Mn, Fe, and Ni)
,”
Phys. Rev. B
46
,
5425
5433
(
1992
).
38.
K. Z.
Du
 et al, “
Weak van der Waals stacking, wide-range band gap, and Raman study on ultrathin layers of metal phosphorus trichalcogenides
,”
ACS Nano
10
,
1738
1743
(
2016
).
39.
A.
Louisy
,
G.
Ouvrard
,
D. M.
Schleich
, and
R.
Brec
, “
Physical properties and lithium intercalates of CrPS4
,”
Solid State Commun.
28
,
61
66
(
1978
).
40.
Q. L.
Pei
 et al, “
Spin dynamics, electronic, and thermal transport properties of two-dimensional CrPS4 single crystal
,”
J. Appl. Phys.
119
,
043902
(
2016
).
41.
J. U.
Lee
 et al, “
Ising-type magnetic ordering in atomically thin FePS3
,”
Nano Lett.
16
,
7433
7438
(
2016
).
42.
C. R. S.
Haines
 et al, “
Pressure-induced electronic and structural phase evolution in the van der Waals compound FePS3
,”
Phys. Rev. Lett.
121
,
266801
(
2018
).
43.
Y.
Wang
 et al, “
Emergent superconductivity in an iron-based honeycomb lattice initiated by pressure-driven spin-crossover
,”
Nat. Commun.
9
,
1914
(
2018
).
44.
A. R.
Wildes
 et al, “
Magnetic structure of the quasi-two-dimensional antiferromagnet NiPS3
,”
Phys. Rev. B
92
,
224408
(
2015
).
45.
M.
Scagliotti
 et al, “
Raman scattering in antiferromagnetic FePS3 and FePSe3 crystals
,”
Phys. Rev. B
35
,
7097
7104
(
1987
).
46.
X.
Wang
 et al, “
Raman spectroscopy of atomically thin two-dimensional magnetic iron phosphorus trisulfide (FePS3) crystals
,”
2D Mater.
3
,
031009
(
2016
).
47.
S.
Lee
 et al, “
Tunneling transport of mono- and few-layers magnetic van der Waals MnPS3
,”
APL Mater.
4
,
086108
(
2016
).
48.
G.
Long
 et al, “
Isolation and characterization of few-layer manganese thiophosphite
,”
ACS Nano
11
,
11330
11336
(
2017
).
49.
M.
Bernasconi
 et al, “
Lattice dynamics of layered MPX3 (M = Mn, Fe, Ni, Zn; X = S, Se) compounds
,”
Phys. Rev. B
38
,
12089
(
1988
).
50.
Y. J.
Sun
 et al, “
Probing the magnetic ordering of anti-ferromagnetic MnPS3 by Raman spectroscopy
,”
J. Phys. Chem. Lett.
10
,
3087
(
2019
).
51.
F.
Parmigiani
and
L.
Sangaletti
, “
Fine structures in the X-ray photoemission spectra of MnO, FeO, CoO, and NiO single crystals
,”
J. Electron Spectrosc. Relat. Phenom.
98-99
,
287
302
(
1999
).
52.
C. R.
Dean
 et al, “
Boron nitride substrates for high-quality graphene electronics
,”
Nat. Nanotechnol.
5
,
722
726
(
2010
).
53.
K.
Kurosawa
 et al, “
Neutron diffraction study on MnPS3 and FePS3
,”
J. Phys. Soc. Jpn.
52
,
3919
3926
(
1983
).
54.
J. M.
Rawson
 et al, “
Antiferromagnetic resonance studies in molecular magnetic materials
,”
J. Phys. Chem. Solids
65
,
727
731
(
2004
).
55.
S. H.
Park
 et al, “
Canted antiferromagnetism and spin reorientation transition in layered inorganic-organic perovskite (C6H5CH2CH2NH3)2MnCl4
,”
Dalt. Trans.
41
,
1237
1242
(
2012
).

Supplementary Material