Protoplanetary disks observed at high resolution with ALMA reveal substructures of dust and gas, indicating locations of potential planets or ongoing planet formation. However, most high-resolution surveys target at solar or intermediate mass stars, with very few disks around M dwarfs. Here we present high-resolution (~ 50 mas) ALMA Band 6 observations of 6 disks around mid-M dwarfs. All six disks are detected in the dust continuum. Four disks showing rings and cavities, while the two faintest disks are smooth.
Three disks have ~10 au cavities, while the disk of 2M0412 has double rings with an inner cavity of ~ 60 au. The two apparently smooth disks have tentative cavities suggested when modeling the continuum emission in the visibility plane with Nuker profiles. We also perform simple radiative transfer calculations with single dust component to fit the SEDs of our sample to constrain the inner hole size of smaller dust grains.