Photovoltaic Effect in the MnZn_1-xCr_xSb Weyl Semimetals

The photovoltaic effect in the MnZn1-xCrxSb Weyl semimetals was studied in a wide spectral range. A correlation in the temperature behavior of the magnetization, photo-voltage, and photocurrent has been found and a sharp increase in the photocurrent below 140 K has been established. Increasing by 50% of the generation of photocurrent is accompanied grows of the Curie temperature by 3%. It is shown that, under the same sample illuminance, the photocurrent and photovoltage attain their maximum values under illumination with an incandescent lamp, rather than with a laser with a wavelength of 830 nm or a led lamp. The photocurrent and photovoltage are increased nonlinearly with increasing power of incident light and the maximum sensitivity is detected in the mid-IR range, increasing from 1.5 mA/W to 20 mA/W with the chromium doping concentration. As the chromium content in the MnZn1-xCrxSb semimetals grows, the drop in resistance changes to a rise under illumination. The possibility of magnetic field control of the photocurrent, photovoltage, and photoresistance with a maximum value at room temperature is demonstrated.