Syntheses, Structures and Properties of Alkali and Alkaline Earth Metal Diamond-Like Compounds Li2MgMSe4 (M = Ge, Sn)

Hongbo Gao; Kewang Zhang; Ailijiang Abudurusuli; Chen Bai; Zhihua Yang; Kangrong Lai; Junjie Li; Shilie Pan

doi:10.3390/ma14206166

Syntheses, Structures and Properties of Alkali and Alkaline Earth Metal Diamond-Like Compounds Li₂MgMSe₄ (M = Ge, Sn)

Materials (Basel). 2021 Oct 18;14(20):6166. doi: 10.3390/ma14206166.

Authors

Hongbo Gao^{1

2}, Kewang Zhang^{1

3}, Ailijiang Abudurusuli^{1

4}, Chen Bai¹, Zhihua Yang¹, Kangrong Lai², Junjie Li¹, Shilie Pan¹

Affiliations

¹ CAS Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics & Chemistry, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011, China.
² Department of Physics, Changji University, Changji 831100, China.
³ College of Physical Science and Technology, Xinjiang University, Urumqi 830046, China.
⁴ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.

Abstract

Two new diamond-like (DL) chalcogenides, Li₂MgGeSe₄ and Li₂MgSnSe₄, have been successfully synthesized using a conventional high-temperature solid-state method. The two compounds crystallize in the non-centrosymmetric space group Pmn2₁ with a = 8.402 (14) Å, b = 7.181 (12) Å, c = 6.728 (11) Å, Z = 2 for Li₂MgSnSe₄, and a = 8.2961 (7) Å, b = 7.0069 (5) Å, c = 6.6116 (6) Å, Z = 2 for Li₂MgGeSe₄. The calculated results show that the second harmonic generation (SHG) coefficients of Li₂MgSnSe₄ (d₃₃ = 12.19 pm/v) and Li₂MgGeSe₄ (d₃₃ = -14.77 pm/v), mainly deriving from the [MSe₄] (M = Ge, Sn) tetrahedral units, are close to the one in the benchmark AgGaS₂ (d₁₄ = 13.7 pm/V). The calculated band gaps for Li₂MgSnSe₄ and Li₂MgGeSe₄ are 2.42 and 2.44 eV, respectively. Moreover, the two compounds are the first series of alkali and alkaline-earth metal DL compounds in the I₂-II-IV-VI₄ family, enriching the structural diversity of DL compounds.

Keywords: chalcogenides; diamond-like structure; infrared nonlinear optical materials; second harmonic generation.

Abstract

Grants and funding