Intensity Interference in a Coherent Spin-Polarized Electron Beam

We investigate the intensity interference between pairs of electrons using a spin-polarized electron beam having a high polarization and a narrow energy width. We observe spin-dependent antibunching on the basis of coincident counts of electron pairs performed with a spin-polarized transmission electron microscope, which could control the spin-polarization without any changes in the electron optics. The experimental results show that the time correlation was only affected by the spin polarization, demonstrating that the antibunching is associated with fermionic statistics. The coherent spin-polarized electron beam facilitates the extraction of intrinsic quantum interference.

Figure 1

Experimental setup for detecting the coincidence of two electrons in conjunction with the SP-TEM. The setup comprises a temporally modulated laser controlled by an acoustic optical modulator (AOM), a liquid crystal (LC) controller, and several wave plates generate spin-polarized electrons with variable polarization and temporal structures. The SP-TEM incorporates an electron biprism to create an interference fringe and separate the coherent electron beam into two positions. A pair of single-electron detectors for coincidence counting are constructed from MCPs and two collectors. These detectors are mechanically retractable to allow observation of the interference fringe created by the electron biprism using a phosphor screen and CCD camera.

Figure 2

Coincidence counts of nonpolarized electrons for a counting time of $7.2\times {10}^3\mathrm{s}$ as a function of the coincidence time.

Figure 3

Differences between the mean coincidence counts of polarized electrons $N_{\mathrm{pol}}$ and nonpolarized electrons $N_{\mathrm{non}}$ in $7.2\times {10}^3\mathrm{s}$ as a function of the coincidence time for (a) positive and (b) negative polarizations. Red dots and blue lines indicate data points and fitting curves, respectively.