High-pressure study of the structural and elastic properties of defect-chalcopyrite HgGa2Se4

Abstract

In this work, we focus on the study of the structural and elastic properties of mercury digallium selenide (HgGa 2 Se 4) which belongs to the family of AB 2 X 4 ordered-vacancy compounds with tetragonal defect chalcopyrite structure. We have carried out high-pressure x-ray diffraction measurements up to 13.2 GPa. Our measurements have been complemented and compared with total-energy ab initio calculations. The equation of state and the axial compressibilities for the lowpressure phase of HgGa 2 Se 4 have been experimentally and theoretically determined and compared to other related ordered-vacancy compounds. The theoretical cation-anion and vacancy-anion distances in HgGa 2 Se 4 have been determined. The internal distance compressibility in HgGa 2 Se 4 has been compared with those that occur in binary HgSe and eÀGaSe compounds. It has been found that the Hg-Se and Ga-Se bonds behave in a similar way in the three compounds. It has also been found that bulk compressibility of the compounds decreases following the sequence "e-GaSe > HgGa 2 Se 4 > HgSe." Finally, we have studied the pressure dependence of the theoretical elastic constants and elastic moduli of HgGa 2 Se 4. Our calculations report that the low-pressure phase of HgGa 2 Se 4 becomes mechanically unstable above 13.3 GPa. V

X-ray diffraction study on pressure-induced phase transformations and the equation of state of ZnGa2Te4

“…Among other techniques, they have been studied by XRD, being several pressure-induced transitions reported. [6][7][8][9][10][11][12][13][14][15] The reversibility of these transitions is subject of dispute. In some cases, it has been found that the transitions are not reversible, being metastable polymorphs recovered at ambient conditions after decompression.…”

Phase stability and elastic properties of CuGaSe2 under high pressure

“…The B/G ratios in Table 3 indicate that CGS in P4/mmm and Amm2 are ductile material. The bulk modulus, and elastic constant and B/G ratio calculated from VRH method were widely used to classify type of phase in compounds such as MgCu 2 [31], HgGa 2 Se 4 [32], CdGa 2 Se 4 [33], HgGa 2 Se 4 [34] and HgGa 2 S 4 [35]. Bulk modulus, C 11 , and B/G ratio of CuGaSe 2 increase under high-pressure which related with the defect-chalcopyrite compounds (HgGa 2 Se 4 and HgGa 2 S 4 ) [32,35].…”

HgGa2Se4 under high pressure: An optical absorption study

“…High‐pressure studies of OVCs with A II B 2 III X 4 VI stoichiometry are receiving increasing attention in the last years . The vast majority of these works have been focused on the study of the structural and vibrational properties of A II B 2 III X 4 VI compounds by means of X‐ray diffraction (XRD) and Raman scattering (RS) measurements, respectively.…”

“…The vast majority of these works have been focused on the study of the structural and vibrational properties of A II B 2 III X 4 VI compounds by means of X‐ray diffraction (XRD) and Raman scattering (RS) measurements, respectively. In particular, three high‐pressure works have recently reported the structural and vibrational properties of DC‐HgGa 2 Se 4 under pressure where pressure‐induced phase transitions have been observed . The disordered stannite (DS) structure and the disordered rocksalt (DR) structure have been proposed as the high‐pressure phases of DC‐HgGa 2 Se 4 .…”

“…In particular, three high‐pressure works have recently reported the structural and vibrational properties of DC‐HgGa 2 Se 4 under pressure where pressure‐induced phase transitions have been observed . The disordered stannite (DS) structure and the disordered rocksalt (DR) structure have been proposed as the high‐pressure phases of DC‐HgGa 2 Se 4 . In addition, the DR phase of HgGa 2 Se 4 on downstroke undergoes a phase transition below 2.1 GPa to a phase assigned to a disordered zincblende (DZ) structure .…”