Seminarium Fizyki Politechniki Wrocławskiej
PWr, bud. A1, sala 322
Control of the Electronic and Magnetic Properties of the 2D Magnetic Semiconductor CrPS4
Prof. Nicolas Ubrig
Department of Quantum Matter Physics, University of Geneva
The discovery of magnetism in layered two-dimensional materials offers an unprecedented platform to design the interactions between magnetic and electronic properties. However, using field-effect transistors (FETs) to explore atomically thin magnetic semiconductors with transport measurements is difficult, because the very narrow bands of most 2D magnetic semiconductors cause carrier localization, preventing transistor operation. Here, we show that exfoliated layers of CrPS4 –a 2D layered antiferromagnetic semiconductor whose bandwidth approaches 1 eV– allow the realization of FETs that operate properly down to cryogenic temperature. Using these devices, we perform conductance measurements as a function of temperature and magnetic field, to determine the full magnetic phase diagram, which includes a spin-flop and a spin-flip phase. We find that the magnetoconductance depends strongly on gate voltage, reaching values as high as 5000 % near the threshold for electron conduction. The gate voltage also allows the magnetic states to be tuned, despite the relatively large thickness of the CrPS4 multilayers employed in our study. Our results show the need to employ 2D magnetic semiconductors with sufficiently large bandwidth to realize properly functioning transistors, and identify a candidate material to realize a fully gate-tunable half-metallic conductor.
