Premature end of rental contract

Short answer: No, it is not!
Since your departure is within your field of responsibility, you cannot "punish" the landlord for it. You still have to fulfil your part and give the contractually agreed termination notice period.
You should mention that you will leave the country, so the landlord can look for a new tenant before your notice period is over. In that case, you only pay rent until the new tenant moves in. Also, you pay no (usage-based) utility charges after you move out.
That said, you can always try to find another mutually agreeable solution by talking to the landlord!

I agree with Beppi. One has to give notice, which I think can be up to 3 months by default.

Extraordinary would be something like the renter dies or maybe is sent to prison or the property is unusable like because of major damage caused by a storm or accident. Such things would make it impossible for the rental contract to be properly fulfilled. One losing a job is not. If it were, then a landlord could equally claim they want to throw a renter out because they lost their job. This would be unthinkable although it could theoretically lead to the situation that the renter could not pay their rent which is of course a condition of the contract. But one should not be forced to be homeless since they can find a new job or other means to pay the rent. Most long term residents would look to social assistance if nothing else to see that they pay their rent. So the rules have obvious advantages and disadvantages.

TominStuttgart wrote:

For the landlord to not charge you for time after you leave would be voluntary but a nice one might do it if they rent it out to someone new without any lapse. Sure doesn't hurt to ask!

Not quite correct: If the apartment is rented out again within the termination period, the old tenant does not have to pay rent any longer. The rule is: No double rent for the landlord (but also no gap in rent) - nothing voluntary about this!