If you have the opportunity to have wet underfloor heating, then I’d go with this. It is a LOT more efficient than electric underfloor. You can also make it compatible with items like evohome, or nest etc as stated above.
However, if it has to be electric, then there are options from Warmup that have a smart thermostat. While there is no direct integration with smartthings, there appears to be the possibility of having it communicate, although its going to take some custom code/applications and working with other members to sort it. One such thread is below.