Fig. 3.

DFT results and quantum oscillation analysis under strain. (A) Results of DFT band structure calculation along the $\mathrm{\Gamma }$-$X$ direction without strain (${\epsilon }_{xx}=0\%$; blue) and with strain (${\epsilon }_{xx}=-0.2\%$; red) applied along the $a$ axis. (B) Strain-induced modification of extremal orbits at $k_z=0$ from DFT calculation. Blue and red lines refer to the same strain as in A. FSs $F_1$ and $F_4$ correspond to hole bands and $F_2$ and $F_3$ to electron bands. (C) Experimental results for SdH oscillations after subtracting the background at temperatures $T=$2, 3, 5, 7, and 10 K for sample S2. The upper plot is for ${\epsilon }_{xx}=$ 0$\%$, and the lower plot is for ${\epsilon }_{xx}=$ –0.14$\%$. (D) FFT results at various ${\epsilon }_{xx}$. Blue lines indicate the frequencies at 0 ${\epsilon }_{xx}$, and red lines are located at the frequencies at −0.15$\%$ strain. (E) SdH oscillation frequencies of the 4 extremal orbits $F_{\mathrm{1,2,3,4}}$ as a function of strain ${\epsilon }_{xx}$. The numerical values of the slopes are given in the figure. (F) Effective cyclotron masses of the 4 extremal orbits $F_{\mathrm{1,2,3,4}}$ as a function of strain, with slopes given in the figure.