Citation: 
Junhui Yuan, Kanhao Xue, Xiangshui Miao, Lei Ye. A family of flexible twodimensional semiconductors: MgMX_{2}Y_{6 }(M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te)[J]. Journal of Semiconductors, 2023, 44(4): 042101. doi: 10.1088/16744926/44/4/042101
****
Junhui Yuan, Kanhao Xue, Xiangshui Miao, Lei Ye. 2023: A family of flexible twodimensional semiconductors: MgMX_{2}Y_{6 }(M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te). Journal of Semiconductors, 44(4): 042101. doi: 10.1088/16744926/44/4/042101

A family of flexible twodimensional semiconductors: MgMX_{2}Y_{6 }(M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te)
DOI: 10.1088/16744926/44/4/042101
More Information

Abstract
Inspired by the recently predicted 2D MX_{2}Y_{6} (M = metal element; X = Si/Ge/Sn; Y = S/Se/Te), we explore the possible applications of alkaline earth metal (using magnesium as example) in this family based on the idea of element replacement and valence electron balance. Herein, we report a new family of 2D quaternary compounds, namely MgMX_{2}Y_{6} (M = Ti/Zr/Hf; X = Si/Ge; Y = S/Se/Te) monolayers, with superior kinetic, thermodynamic and mechanical stability. In addition, our results indicate that MgMX_{2}Y_{6} monolayers are all indirect band gap semiconductors with band gap values ranging from 0.870 to 2.500 eV. Moreover, the band edges and optical properties of 2D MgMX_{2}Y_{6} are suitable for constructing multifunctional optoelectronic devices. Furthermore, for comparison, the mechanical, electronic and optical properties of In_{2}X_{2}Y_{6} monolayers have been discussed in detail. The success of introducing Mg into the 2D MX_{2}Y_{6} family indicates that more potential materials, such as Ca and Srbased 2D MX_{2}Y_{6} monolayers, may be discovered in the future. Therefore, this work not only broadens the existing family of 2D semiconductors, but it also provides beneficial results for the future. 
References
[1] Novoselov K S, Geim A K, Morozov S V, et al. Electric field effect in atomically thin carbon films. Science, 2004, 306, 666 doi: 10.1126/science.1102896[2] Akinwande D, Huyghebaert C, Wang C H, et al. Graphene and twodimensional materials for silicon technology. Nature, 2019, 573, 507 doi: 10.1038/s4158601915739[3] Yuan J H, Yu N N, Xue K H, et al. Ideal strength and elastic instability in singlelayer 8Pmmn borophene. RSC Adv, 2017, 7, 8654 doi: 10.1039/C6RA28454J[4] Yuan J H, Yu N N, Xue K H, et al. Stability, electronic and thermodynamic properties of aluminene from firstprinciples calculations. Appl Surf Sci, 2017, 409, 85 doi: 10.1016/j.apsusc.2017.02.238[5] Balendhran S, Walia S, Nili H, et al. Elemental analogues of graphene: Silicene, germanene, stanene, and phosphorene. Small, 2015, 11, 640 doi: 10.1002/smll.201402041[6] Yuan P W, Zhang T, Sun J T, et al. Recent progress in 2D groupV elemental monolayers: Fabrications and properties. J Semicond, 2020, 41, 081003 doi: 10.1088/16744926/41/8/081003[7] Wang Y X, Qiu G, Wang R X, et al. Fieldeffect transistors made from solutiongrown twodimensional tellurene. Nat Electron, 2018, 1, 228 doi: 10.1038/s4192801800584[8] Liu Y, Duan X D, Huang Y, et al. Twodimensional transistors beyond graphene and TMDCs. Chem Soc Rev, 2018, 47, 6388 doi: 10.1039/C8CS00318A[9] Tong L, Peng Z R, Lin R F, et al. 2D materialsbased homogeneous transistormemory architecture for neuromorphic hardware. Science, 2021, 373, 1353 doi: 10.1126/science.abg3161[10] MoralesGarcía Á, CalleVallejo F, Illas F. MXenes: New horizons in catalysis. ACS Catal, 2020, 10, 13487 doi: 10.1021/acscatal.0c03106[11] Wang L, Shi Y P, Liu M F, et al. Intercalated architecture of MA_{2}Z_{4} family layered van der Waals materials with emerging topological, magnetic and superconducting properties. Nat Commun, 2021, 12, 2361 doi: 10.1038/s41467021223248[12] Ding W J, Zhu J B, Wang Z, et al. Prediction of intrinsic twodimensional ferroelectrics in In_{2}Se_{3} and other III_{2}VI_{3} van der Waals materials. Nat Commun, 2017, 8, 14956 doi: 10.1038/ncomms14956[13] Deng J, Deng D H, Bao X H. Robust catalysis on 2D materials encapsulating metals: Concept, application, and perspective. Adv Mater, 2017, 29, 1606967 doi: 10.1002/adma.201606967[14] Lemme M C, Akinwande D, Huyghebaert C, et al. 2D materials for future heterogeneous electronics. Nat Commun, 2022, 13, 1392 doi: 10.1038/s41467022290014[15] Tang K, Wang Y, Gong C H, et al. Electronic and photoelectronic memristors based on 2D materials. Adv Elect Mater, 2022, 8, 2101099 doi: 10.1002/aelm.202101099[16] Anichini C, Czepa W, Pakulski D, et al. Chemical sensing with 2D materials. Chem Soc Rev, 2018, 47, 4860 doi: 10.1039/C8CS00417J[17] Wu F, Tian H, Shen Y, et al. Vertical MoS_{2} transistors with sub1nm gate lengths. Nature, 2022, 603, 259 doi: 10.1038/s41586021043233[18] Li X F, Yu Z Q, Xiong X, et al. Highspeed black phosphorus fieldeffect transistors approaching ballistic limit. Sci Adv, 2019, 5, eaau3194 doi: 10.1126/sciadv.aau3194[19] Wang Y C, Lv J, Zhu L, et al. CALYPSO: A method for crystal structure prediction. Comput Phys Commun, 2012, 183, 2063 doi: 10.1016/j.cpc.2012.05.008[20] Glass C W, Oganov A R, Hansen N. USPEX—Evolutionary crystal structure prediction. Comput Phys Commun, 2006, 175, 713 doi: 10.1016/j.cpc.2006.07.020[21] Yu W Y, Niu C Y, Zhu Z L, et al. Atomically thin binary VV compound semiconductor: A firstprinciples study. J Mater Chem C, 2016, 4, 6581 doi: 10.1039/C6TC01505K[22] Jin X, Tao L, Zhang Y Y, et al. Intrinsically scalefree ferroelectricity in twodimensional M_{2}X_{2}Y_{6}. Nano Res, 2022, 15, 3704 doi: 10.1007/s1227402139195[23] Miao N H, Li W, Zhu L G, et al. Tunable phase transitions and high photovoltaic performance of twodimensional In_{2}Ge_{2}Te_{6} semiconductors. Nanoscale Horiz, 2020, 5, 1566 doi: 10.1039/D0NH00395F[24] Hao K R, Ma X Y, Lyu H Y, et al. The atlas of ferroicity in twodimensional MGeX_{3} family: Roomtemperature ferromagnetic half metals and unexpected ferroelectricity and ferroelasticity. Nano Res, 2021, 14, 4732 doi: 10.1007/s1227402134156[25] Hao K R, Ma X Y, Zhang Z, et al. Ferroelectric and roomtemperature ferromagnetic semiconductors in the 2D M_{I}M_{II}Ge_{2}X_{6} family: Firstprinciples and machine learning investigations. J Phys Chem Lett, 2021, 12, 10040 doi: 10.1021/acs.jpclett.1c02782[26] Nityananda R, Hohenberg P, Kohn W. Inhomogeneous electron gas. Reson, 2017, 22, 809 doi: 10.1007/s1204501705293[27] Blöchl P E. Projector augmentedwave method. Phys Rev B, 1994, 50, 17953 doi: 10.1103/PhysRevB.50.17953[28] Kresse G, Joubert D. From ultrasoft pseudopotentials to the projector augmentedwave method. Phys Rev B, 1999, 59, 1758 doi: 10.1103/PhysRevB.59.1758[29] Kresse G, Furthmüller J. Efficiency of abinitio total energy calculations for metals and semiconductors using a planewave basis set. Comput Mater Sci, 1996, 6, 15 doi: 10.1016/09270256(96)000080[30] Kresse G, Furthmüller J. Efficient iterative schemes for ab initio totalenergy calculations using a planewave basis set. Phys Rev B, 1996, 54, 11169 doi: 10.1103/PhysRevB.54.11169[31] Perdew J P, Burke K, Ernzerhof M. Generalized gradient approximation made simple. Phys Rev Lett, 1996, 77, 3865 doi: 10.1103/PhysRevLett.77.3865[32] Xue K H, Yuan J H, Fonseca L R C, et al. Improved LDA1/2 method for band structure calculations in covalent semiconductors. Comput Mater Sci, 2018, 153, 493 doi: 10.1016/j.commatsci.2018.06.036[33] Yuan J H, Chen Q, Fonseca L R C, et al. GGA1/2 selfenergy correction for accurate band structure calculations: The case of resistive switching oxides. J Phys Commun, 2018, 2, 105005 doi: 10.1088/23996528/aade7e[34] Krukau A V, Vydrov O A, Izmaylov A F, et al. Influence of the exchange screening parameter on the performance of screened hybrid functionals. J Chem Phys, 2006, 125, 224106 doi: 10.1063/1.2404663[35] Togo A, Oba F, Tanaka I. Firstprinciples calculations of the ferroelastic transition between rutiletype and CaCl_{2}type SiO_{2} at high pressures. Phys Rev B, 2008, 78, 134106 doi: 10.1103/PhysRevB.78.134106[36] Jin H, Tan X X, Wang T, et al. Discovery of twodimensional multinary component photocatalysts accelerated by machine learning. J Phys Chem Lett, 2022, 13, 7228 doi: 10.1021/acs.jpclett.2c01862[37] Kamal C, Ezawa M. Arsenene: Twodimensional buckled and puckered honeycomb arsenic systems. Phys Rev B, 2015, 91, 085423 doi: 10.1103/PhysRevB.91.085423[38] Liu Z, Wang H D, Sun J Y, et al. PentaPt_{2}N_{4}: An ideal twodimensional material for nanoelectronics. Nanoscale, 2018, 10, 16169 doi: 10.1039/C8NR05561K[39] Yuan J H, Song Y Q, Chen Q, et al. Singlelayer planar pentaX_{2}N_{4} (X = Ni, Pd and Pt) as directbandgap semiconductors from first principle calculations. Appl Surf Sci, 2019, 469, 456 doi: 10.1016/j.apsusc.2018.11.041[40] Born M, Huang K. Dynamical theory of crystal lattices. Oxford: Clarendon Press, 1954[41] Tang W, Sanville E, Henkelman G. A gridbased Bader analysis algorithm without lattice bias. J Phys: Condens Matter, 2009, 21, 084204 doi: 10.1088/09538984/21/8/084204[42] Liu F, Ming P B, Li J. Ab initio calculation of ideal strength and phonon instability of graphene under tension. Phys Rev B, 2007, 76, 064120 doi: 10.1103/PhysRevB.76.064120[43] Andrew R C, Mapasha R E, Ukpong A M, et al. Mechanical properties of graphene and boronitrene. Phys Rev B, 2012, 85, 125428 doi: 10.1103/PhysRevB.85.125428[44] Li J W, Medhekar N V, Shenoy V B. Bonding charge density and ultimate strength of monolayer transition metal dichalcogenides. J Phys Chem C, 2013, 117, 15842 doi: 10.1021/jp403986v[45] Li J, Zhou W H, Xu L L, et al. Revealing the weak Fermi level pinning effect of 2D semiconductor/2D metal contact: A case of monolayer In_{2}Ge_{2}Te_{6} and its Janus structure In_{2}Ge_{2}Te_{3}Se_{3}. Mater Today Phys, 2022, 26, 100749 doi: 10.1016/j.mtphys.2022.100749[46] Yuan J H, Zhang B, Song Y Q, et al. Planar pentatransition metal phosphide and arsenide as narrowgap semiconductors with ultrahigh carrier mobility. J Mater Sci, 2019, 54, 7035 doi: 10.1007/s10853019033804 
Proportional views