Germanic Shoe from Friesland

[Crispianus]

Could a carbatina be made in 1 mm leather? Any roman shoes in such kind of leather?

Sure, and as long as you walk carefully and majestically on highly polished marble floors, they'd last a while as well ;-)
More seriously, as Ivor said, it doesn't really make sense for carbatinae, but there is thin leather used for uppers, also typically it is hard to say anything specific about original thickness with finds. If you look at the calcei e.g. on the Ara Pacis, the upper needed to be very thin leather (if it was leather at all) to define the wearer's toes anywhere near to how it is depicted.

Of course leather degrades over time and Stretches/shrinks/distorts being organic and skin, its really one of the major problems for reconstructing footware from archaeological remains and why patterns need to be carefully thought out....
I think to make shoes where the toes show, thin leather works fine, but I would use a soft flexible goat skin 1.5-2mm thick( a normal goatskin thickness not deliberatly thinned) over 2mm would probably be too much though the bigger older goats can be very thick... the key to this though I think is soft flexible leather rather then the thickness as you can always thin out a piece of leather that is suitable but otherwise too thick.. pick the leather to suit the shoe....