Vacancies and spin–phonon coupling in CrSi_0.8Ge_0.1Te₃

Abstract

We report temperature‐dependent Raman scattering and magnetization studies of van der Waals ferromagnetic compound CrSi0.8Ge0.1Te3. Magnetic susceptibility measurements revealed dominant ferromagnetic interactions below TC which shift to the lower values due to the presence of vacancies. A Raman active mode, additional to the ones predicted by symmetry in the parent compounds, has been observed. This Ag symmetry mode most likely emerges as a consequence of the atomic vacancies on Si/Ge site. Presence of the strong spin–phonon coupling at temperature around 210 K is indicated by deviations from conventional phonon self‐energy temperature dependence of all analysed modes.

Polaronic Conductivity in Cr2Ge2Te6 Single Crystals

“…[ 1 ] The mechanism of intrinsic long‐range magnetic order in monolayers of 2D materials such as CrI 3 and bilayer Cr 2 Ge 2 Te 6 might be exploited for design of novel spin‐related devices. [ 2,3 ] They can be stacked into heterostructures [ 4–9 ] and their physical properties are highly tunable by carrier doping, [ 10–13 ] strain, [ 14–16 ] vacancies, [ 17–21 ] pressure, [ 22–26 ] and electric field. [ 27–30 ]…”

“…[1] The mechanism of intrinsic long-range magnetic order in monolayers of 2D materials such as CrI 3 and bilayer Cr 2 Ge 2 Te 6 might be exploited for design of novel spin-related devices. [2,3] They can be stacked into heterostructures [4][5][6][7][8][9] and their physical properties are highly tunable by carrier doping, [10][11][12][13] strain, [14][15][16] vacancies, [17][18][19][20][21] pressure, [22][23][24][25][26] and electric field. [27][28][29][30] Cr 2 Ge 2 Te 6 exhibits a paramagnetic (PM) to ferromagnetic (FM) transition with the Curie temperature (T c ) of ≈61-68 K in bulk, an out-of-plane easy axis and negligible coercivity.…”

Raman Shifts in Two-Dimensional van der Waals Magnets Reveal Magnetic Texture Evolution

“…To further verify that changes of skyrmion bubbles can be manifested as Raman shifts, we apply this approach to Cr 2 Si 2 Te 6 , another vdW magnet that has the same structure as Cr 2 Ge 2 Te 6 and exhibits a similar Heisenberg behavior. , Cr 2 Si 2 Te 6 can also support magnetic skyrmion bubbles at temperatures below its T c (∼33 K) . For Cr 2 Si 2 Te 6 thin films field-cooled (400 Oe) to 10 K, we observe a similar field-induced shift in the peak position of its most prominent E g 3 mode (Figure S7a,b), which involves atomic displacements of Te atoms. , It is worth mentioning that the Raman shift observed for Cr 2 Si 2 Te 6 is slightly smaller than that of Cr 2 Ge 2 Te 6 , which may be related to different magnetic skyrmion changes in the two materials, and/or the smaller spin–phonon coupling in Cr 2 Si 2 Te 6 , which we estimate to be 0.097 ± 0.040 cm –1 (Figure S7c). , Nevertheless, the Raman shifts observed in field-cooled Cr 2 Si 2 Te 6 thin films further confirm the intimate connection between the spin–phonon interaction and magnetic texture changes.…”

“…43 For Cr 2 Si 2 Te 6 thin films field-cooled (400 Oe) to 10 K, we observe a similar fieldinduced shift in the peak position of its most prominent E g 3 mode (Figure S7a,b), which involves atomic displacements of Te atoms. 44,45 spin−phonon coupling in Cr 2 Si 2 Te 6 , which we estimate to be 0.097 ± 0.040 cm −1 (Figure S7c). 28,38 Nevertheless, the Raman shifts observed in field-cooled Cr 2 Si 2 Te 6 thin films further confirm the intimate connection between the spin− phonon interaction and magnetic texture changes.…”

Polaronic Conductivity in Cr$_2$Ge$_2$Te$_6$ Single Crystals

“…1 The mechanism of intrinsic longrange magnetic order in monolayers of 2D materials such as CrI 3 and bilayer Cr 2 Ge 2 Te 6 might be exploited for design of novel spin-related devices. 2,3 They can be stacked into heterostructures [4][5][6][7][8][9] and their physical properties are highly tunable by carrier doping, [10][11][12][13] strain, [14][15][16] vacancies, [17][18][19][20][21] pressure [22][23][24][25][26] and electric field. [27][28][29][30] Cr 2 Ge 2 Te 6 exhibits a paramagnetic (PM) to ferromagnetic (FM) transition with the Curie temperature (T c ) of 61 ∼ 68 K in bulk, an out-of-plane easy axis and negligible coercivity.…”