高压下MgN<sub>8</sub>晶体结构理论模拟与物性研究

缪宇; 刘思远; 马雪姣; 金哲学

doi:10.11858/gywlxb.20190818

高压下MgN₈晶体结构理论模拟与物性研究

doi: 10.11858/gywlxb.20190818

缪宇^1,,
刘思远¹,
马雪姣¹,
金哲学^2,*, ,

1.
延边大学理学院，吉林延吉　133000
2.
延边大学工学院，吉林延吉　133000

基金项目: 国家自然科学基金（11764043）；吉林省科技厅发展计划项目（20180101226JC）

详细信息

作者简介:
缪　宇(1999－)，男，本科，主要从事高压结构计算研究. E-mail: 15053219411@163.com

通讯作者:
金哲学(1971－)，男，讲师，主要从事计算机网络通信技术与研发研究.E-mail: jinzhexue@ybu.edu.cn

中图分类号: O521.2
计量
- 文章访问数: 8159
- HTML全文浏览量: 3968
- PDF下载量: 61
出版历程
- 收稿日期: 2019-08-06
- 修回日期: 2019-09-25

Theoretical Simulation and Physical Properties of MgN₈ Crystal Structure under High Pressure

MIAO Yu^1
,,
LIU Siyuan¹,
MA Xuejiao¹,
JIN Zhexue^{2,*
, ,}

1.
Department of Physics, Yanbian University, Yanji 133000, Jilin, China
2.
Department of Engineering, Yanbian University, Yanji 133000, Jilin, China

摘要

摘要: 基于密度泛函理论第一性原理的方法，使用CALYPSO结构搜索技术结合VASP软件，在0～100 GPa压强范围内对MgN₈的晶体结构进行预测，并对预测的结构进行系统研究。结果表明：在常压下，空间群为P4/mbm的α-MgN₈晶体结构的焓值最低；当压强达到24.3 GPa和68.3 GPa时发生相变，分别相变成空间群为P4/mnc的β-MgN₈相和空间群为Cmcm的γ-MgN₈相，两次相变均为对应体积坍塌的一级相变。电子性质计算结果表明，α-MgN₈相的导带与价带之间具有3.09 eV的带隙，表明该结构具有非金属性；β相和γ相具有明显的金属特征。Bader电荷转移计算表明，随着压力的增加，Mg原子向N原子转移的电荷逐渐增多。
- 高压 /
- 第一性原理 /
- 晶体结构预测 /
- MgN₈ /
- 电荷转移 /
- 相变
Abstract: Based on the first principle of density functional theory, the crystal structure of MgN₈ was predicted in the pressure range of 0–100 GPa by using CALYPSO structure search technique and VASP software. After systematically studying the predicted structure, it was found that the enthalpy of α-MgN₈ crystal with space group P4/mbm was the lowest at ambient pressure. The phase was changed to β-MgN₈ phase of P4/mnc and γ-MgN₈ phase of Cmcm when the pressure reached 24.3 GPa and 68.3 GPa, respectively. And both of the phase transitions were the first order phase transition of corresponding volume collapse. The calculated results of electronic properties suggested that the existence of a band gap of 3.09 eV between the conduction band and valence band of α-MgN₈ phase revealed the non-gold properties of the structure, whereas the obvious metal characteristics appeared in the β-MgN₈ phase and γ-MgN₈ phase. Bader charge transfer calculation showed that the charge which transferred from Mg atom to N atom, increased gradually with the increase of pressure.
- high pressure /
- first-principles /
- crystal structure prediction /
- MgN₈ /
- charge transfer /
- phase transition

HTML全文

图 1 MgN₈的焓差曲线以及α-MgN₈、β-MgN₈、γ-MgN₈相体积随压强的变化关系

Figure 1. Calculated enthalpies per formula unit of pressure of MgN₈ and the calculated volume versus pressure of α-MgN₈, β-MgN₈ and γ-MgN₈

下载: 全尺寸图片幻灯片

图 2 α-MgN₈、β-MgN₈和γ-MgN₈相的晶体结构

Figure 2. Crystal structures of α-MgN₈, β-MgN₈ and γ-MgN₈

下载: 全尺寸图片幻灯片

图 3 α-MgN₈、β-MgN₈、γ-MgN₈相声子色散关系和声子态密度

Figure 3. Phonon-dispersion curves and the phonon density of states of α-MgN₈, β-MgN₈ and γ-MgN₈

下载: 全尺寸图片幻灯片

图 4 α-MgN₈、β-MgN₈、γ-MgN₈相的能带结构和电子态密度

Figure 4. Band structure and partial density of states of α-MgN₈, β-MgN₈ and γ-MgN₈

下载: 全尺寸图片幻灯片

图 5 α-MgN₈、β-MgN₈、γ-MgN₈相的电子局域函数

Figure 5. Electron localization function of α-MgN₈, β-MgN₈ and γ-MgN₈

下载: 全尺寸图片幻灯片

表 1 α-MgN₈、β-MgN₈和γ-MgN₈相的平衡态晶格常数

Table 1. Lattice parameters of α-MgN₈, β-MgN₈ and γ-MgN₈ in the equilibrium state

Phase	Pressure/GPa	a/Å	b/Å	c/Å	α/(°)	β/(°)	γ/(°)
α-MgN₈ (P4/mbm)	0	5.913	5.913	6.572	90.0	90.0	90.0
β-MgN₈ (P4/mnc)	24.3	6.219	6.219	3.724	90.0	90.0	90.0
γ-MgN₈ (Cmcm)	68.3	4.167	4.167	8.680	90.0	90.0	51.1

下载: 导出CSV

表 2 α-MgN₈、β-MgN₈和γ-MgN₈相的平衡态晶格常数和原子位置

Table 2. Lattice parameters and atomic coordinate of α-MgN₈, β-MgN₈ and γ-MgN₈ in the equilibrium state

Phase	Pressure/GPa	Atoms	Wyckoff position	x	y	z
α-MgN₈ (P4/mbm)	0	Mg	2b	0.000	0.000	0.500
		N1	2a	0.000	0.000	0.000
		N2	2c	0.000	0.500	0.500
		N3	4e	0.000	0.000	0.821
		N4	4f	0.000	0.500	0.915
		N5	4h	0.859	0.359	0.500
β-MgN₈ (P4/mnc)	24.3	Mg	2a	0.000	0.000	1.000
β-MgN₈ (P4/mnc)	24.3	N	16i	0.416	0.219	0.823
γ-MgN₈ (Cmcm)	68.3	Mg	8g	0.624	–0.376	1.250
		N1	16h	0.226	–0.135	0.617
		N2	16h	1.115	0.471	1.386

下载: 导出CSV

表 3 α-MgN₈、β-MgN₈、γ-MgN₈相电荷转移

Table 3. Calculated Bader charges of α-MgN₈, β-MgN₈ and γ-MgN₈

Phase	Pressure/GPa	Atoms	Number	Charge value/e	Charge transfer/e
α-MgN₈ (P4/mbm)	0	Mg	1	6.26	1.74
		N1	1	4.84	0.16
		N2	1	4.86	0.13
		N3	2	5.04	–0.04
		N4	2	5.46	–0.46
		N5	2	5.52	–0.52
β-MgN₈ (P4/mnc)	24.3	Mg	1	6.06	1.94
β-MgN₈ (P4/mnc)	24.3	N	8	5.24	–0.24
γ-MgN₈ (Cmcm)	68.3	Mg	1	5.80	2.20
		N1	4	5.28	–0.28
		N2	4	5.27	–0.27

下载: 导出CSV

参考文献(24)

[1]	GROCHALA W, HOFFMANN R, FENG J, et al. The chemical imagination at work in very tight places [J]. Angewandte Chemie International Edition, 2007, 46(20): 3620–3642. doi: 10.1002/anie.200602485
[2]	HEMLEY R J. Effects of high pressure on molecules [J]. Annual Review of Physical Chemistry, 2000, 51(1): 763–800. doi: 10.1146/annurev.physchem.51.1.763
[3]	SCHETTINO V, BINI R. Molecules under extreme conditions: chemical reactions at high pressure [J]. Physical Chemistry Chemical Physics, 2003, 5(10): 1951–1965. doi: 10.1039/b301381b
[4]	李鑫, 马雪姣, 高文泉, 等. 高压下Ir₂P晶体结构预测与物理性质 [J]. 高压物理学报, 2019, 33(1): 011103. doi: 10.11858/gywlxb.20180645 LI X, MA X J, GAO W Q, et al. Evolution of crystal structures and electronic properties for Ir₂P under high pressure [J]. Chinese Journal of High Pressure Physics, 2019, 33(1): 011103. doi: 10.11858/gywlxb.20180645
[5]	MA X J, LI X, ZHOU D, et al. Phase diagram and bonding states of Ir-P binary compounds at high pressures [J]. Journal of Alloys and Compounds, 2019, 791: 1257–1262. doi: 10.1016/j.jallcom.2019.03.051
[6]	BRULS R J, HINTZEN H T, METSELAAR R. Preparation and characterisation of MgSiN₂ powders [J]. Journal of Materials Science, 1999, 34(18): 4519–4531. doi: 10.1023/A:1004645407523
[7]	PARKIN I P, NARTOWSKI A M. Solid state metathesis routes to Group IIIa nitrides: comparison of Li₃N, NaN₃, Ca₃N₂ and Mg₃N₂ as nitriding agents [J]. Polyhedron, 1998, 17(16): 2617–2622. doi: 10.1016/S0277-5387(97)00454-3
[8]	KOBASHI M, OKAYAMA N, CHOH T. Synthesis of AlN/Al alloy composites by in situ reaction between Mg₃N₂ and aluminum [J]. Materials Transactions, JIM, 1997, 38(3): 260–265. doi: 10.2320/matertrans1989.38.260
[9]	EREMETS M I, GAVRILIUK A G, TROJAN I A, et al. Single-bonded cubic form of nitrogen [J]. Nature Materials, 2004, 3(8): 558–563. doi: 10.1038/nmat1146
[10]	LORENZ H, KÜHNE U, HOHLFELD C, et al. Influence of MgO on the growth of cubic boron nitride using the catalyst Mg3N₂ [J]. Journal of Materials Science Letters, 1988, 7(1): 23–24. doi: 10.1007/BF01729904
[11]	PAPACONSTANTOPOULOS D A, PICKETT W E, KLEIN B M, et al. Electronic properties of transition-metal nitrides: the group-V and group-VI nitrides VN, NbN, TaN, CrN, MoN, and WN [J]. Physical Review B, 1985, 31(2): 752–761. doi: 10.1103/PhysRevB.31.752
[12]	MENG Y, MAO H K, ENG P J, et al. The formation of sp³ bonding in compressed BN [J]. Nature Materials, 2004, 3(2): 111–114. doi: 10.1038/nmat1060
[13]	RAZA Z, PICKARD C J, PINILLA C, et al. High energy density mixed polymeric phase from carbon monoxide and nitrogen [J]. Physical Review Letters, 2013, 111(23): 235501. doi: 10.1103/PhysRevLett.111.235501
[14]	KNITTLE E, WENTZCOVITCH R M, JEANLOZ R, et al. Experimental and theoretical equation of state of cubic boron nitride [J]. Nature, 1989, 337(6205): 349–352. doi: 10.1038/337349a0
[15]	XIA Y, LI Q, MA Y M. Novel superhard polymorphs of Be₃N₂ predicted by first-principles [J]. Computational Materials Science, 2010, 49(1): S76–S79. doi: 10.1016/j.commatsci.2010.01.045
[16]	ZHU S S, PENG F, LIU H Y, et al. Stable calcium nitrides at ambient and high pressures [J]. Inorganic Chemistry, 2016, 55(15): 7550–7555. doi: 10.1021/acs.inorgchem.6b00948
[17]	JI D P, CHONG X Y, FENG J. Electronic, mechanical and hydrogen storage properties of novel Mg₃N₂ [J]. Journal of Alloys and Compounds, 2019, 800: 8–15. doi: 10.1016/j.jallcom.2019.06.021
[18]	WANG Y C, LV J, ZHU L, et al. Crystal structure prediction via particle-swarm optimization [J]. Physical Review B, 2010, 82(9): 094116. doi: 10.1103/PhysRevB.82.094116
[19]	MONKHORST H J, PACK J D. Special points for Brillouin-zone integrations [J]. Physical Review B, 1976, 13(12): 5188. doi: 10.1103/PhysRevB.13.5188
[20]	PERDEW J P, BURKE K, ERNZERHOF M. Generalized gradient approximation made simple [J]. Physical Review Letters, 1996, 77(18): 3865–3868. doi: 10.1103/PhysRevLett.77.3865
[21]	BORN M, HUANG K. Dynamical theory of crystal lattices [J]. American Journal of Physics, 1954, 39(2): 113–127.
[22]	BECKE A D, EDGECOMBE K E. A simple measure of electron localization in atomic and molecular systems [J]. The Journal of Chemical Physics, 1990, 92(9): 5397–5403. doi: 10.1063/1.458517
[23]	BADER R F W. Atoms in molecules [J]. Accounts of Chemical Research, 1985, 18(1): 9–15. doi: 10.1021/ar00109a003
[24]	OGANOV A R, CHEN J H, GATTI C, et al. Ionic high-pressure form of elemental boron [J]. Nature, 2009, 457(7231): 863–867. doi: 10.1038/nature07736