Exotic magnetic and electronic properties of layered CrI3 single crystals under high pressure

Pressure-driven structural phase transitions and metallization in the two-dimensional ferromagnetic semiconductor CrBr3

“…10,11 On further compression up to 28.0 GPa, an electronic topological transition (ETT) occurred, accompanying the emergence of semiconductor-to-metal transformation in CrCl 3 . 10,11 For chromium triiodide, the pressure-driven metallization and magnetic transformation took place simultaneously as the pressure increased above 22.0 GPa, which was corroborated by the theoretical calculation results with the overlap of valence bands and conduction bands, 12 whereas, for chromium tribromide, the high-pressure structural, magnetic and vibrational behaviours were studied through X-ray powder diffraction, neutron powder diffraction and Raman spectroscopy up to a limited pressure of 23.0 GPa. 13 Their results demonstrated that CrBr 3 experienced a pressure-induced IPT within the pressure range of 2.5–7.0 GPa.…”

“…† Generally speaking, the electrical conductivity of a semiconductor increases profoundly with the rise of temperature (dσ/dT > 0), whereas a metal has a faintly negative temperature dependence in the electrical conductivity relationship (dσ/dT < 0). 11,12,[15][16][17][18][19][20][30][31][32] As seen in Fig. 6a and b, during compression, CrBr 3 exhibited a positive dσ/dT relationship below 23.8 GPa, which is characteristic of the semiconducting behaviour.…”

“…Therefore, the magnetic transition of CrBr 3 is possibly accompanied by the occurrence of metallization, which has also been reported in the chromium triiodide with a similar crystalline structure of 2D chromium trihalide. 12 Several crucial crystallographic parameters of the sample, including the lattice constants (a, b and c), normalized lattice constants (a/a 0 , b/b 0 and c/c 0 ), lattice constant ratios (a/c and b/c), unit cell volume (V), normalized unit cell volume (V/V 0 ), Cr-Br-Cr bond angle, Cr-Br bond length, nearest Cr-Cr bond length and 2 nd nearest Cr-Cr bond length, as a function of pressure were successfully obtained, and a series of representative results are displayed in Fig. 11 and Fig.…”

“…9 The application of pressure offers an effective approach of manipulating the structural, magnetic and electrical transport characteristics of chromium trihalides. [10][11][12][13] Despite the considerable high-pressure investigations on CrCl 3 and CrI 3 , only one unique available research on CrBr 3 under high pressure has been reported to date. [10][11][12][13] More recently, CrCl 3 has been revealed to endure an isostructural phase transition (IPT) at 9.9 GPa, which was concurrent with the magnetic crossover from ferromagnetic (FM) to antiferromagnetic (AFM) configurations.…”

“…[10][11][12][13] Despite the considerable high-pressure investigations on CrCl 3 and CrI 3 , only one unique available research on CrBr 3 under high pressure has been reported to date. [10][11][12][13] More recently, CrCl 3 has been revealed to endure an isostructural phase transition (IPT) at 9.9 GPa, which was concurrent with the magnetic crossover from ferromagnetic (FM) to antiferromagnetic (AFM) configurations. 10,11 On further compression up to 28.0 GPa, an electronic topological transition (ETT) occurred, accompanying the emergence of semiconductor-to-metal transformation in CrCl 3 .…”