Quantum Interference Effects in the Magnetopiezoresistance of $\mathrm{I}\mathrm{n}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}\mathrm{G}\mathrm{a}\mathrm{S}\mathrm{b}$ Quasi-One-Dimensional Electron Systems

We measured the low temperature magnetopiezoresistance of a quasi-one-dimensional electron system by fabricating an $\mathrm{I}\mathrm{n}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}\mathrm{G}\mathrm{a}\mathrm{S}\mathrm{b}$ micromechanical cantilever. The magnetopiezoresistance curve showed aperiodic but reproducible oscillation, which was similar to the differential magnetoresistance curve obtained for the same device. A detailed comparison with model calculations strongly suggests that the quantum interference effects that cause the conductance fluctuations in the magnetoresistance are responsible for the peculiar behavior of the magnetopiezoresistance.

Figure 1

(a) Fabricated $\mathrm{I}\mathrm{n}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}\mathrm{G}\mathrm{a}\mathrm{S}\mathrm{b}$ piezoresistive cantilever. (b) Piezoresistance as a function of magnetic field measured at 2.5 K. Because the actuation amplitude was not directly measured at low temperature, the arbitrary unit was used for the vertical axis. (c) The two-terminal magnetoresistance of the same sample obtained after measuring (b). The dotted line ($d{R}_{2\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{m}}/dB$) is the derivative with respect to the mag­netic field.

Figure 2

Fourier transforms obtained for (a) the magnetopiezoresistance [Fig. 1b] and (b) the differential magnetoresistance [Fig. 1c].

Figure 3

Calculated magnetopiezoresistance and differential magnetoresistance.

Figure 4

Cross-correlation functions evaluated for the correlation between (a) experimentally obtained $d{R}_{2\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{m}}/dB$ and $R_{\mathrm{p}\mathrm{i}\mathrm{e}\mathrm{z}\mathrm{o}}$ curves for low (0–2 T) and high (5–7 T) magnetic field regions, and (b) numerically obtained $d{R}_{2\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{m}}/dB$ and strain-induced $R_{\mathrm{p}\mathrm{i}\mathrm{e}\mathrm{z}\mathrm{o}}$, and also $d{R}_{2\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{m}}/dB$ and apparent $R_{\mathrm{p}\mathrm{i}\mathrm{e}\mathrm{z}\mathrm{o}}$.