In California, a landlord is asking a tenant who has another year left on their lease to break the lease. The landlord purchased the property in 2015 for $1.5 million and would now like to upgrade the units, hence raise the rent. The current lease was a 3 year lease and was done while the previous owner still owned the property. The current rent is $1,000 for a 1BD/1BA 600+ unit in San Diego, CA and the new landlord states that the going rate for a unit that same size is on average about $1400 and is willing to give the tenant $400 for every month left on their unit, which comes out to roughly about $4k. My understanding is that if a tenant breaks a lease, they may liable for the remaining months left on the lease, but what about if the landlord wants to break the lease? I can't seem to find any information on leases, only on month-to-month.
You can't legally break a contract: that's what makes it a contract. If you do breach a contract then you arte liable for damages and/or other remedies.
However, what you are describing seems to be the negotiation of a variation of a contract. If there is consideration on both sides (the tenant leaves, the landlord pays - seems OK) then this is not a breach. Such a variation would need to be agreed by both parties.
A landlord could do things that would seem like "breaking the lease", but in fact they effectively can't break a lease (unless they intend to occupy the premise themselves, which they must actually do, and not just use that as a pretense). They might declare that the rent shall be double, but such a declaration has no legal effect, and a court would not enforce a rent-hike in the middle of a lease. They might turn off the water or nail the door shut, but you could sue them (Cal. Civ. Code 1941.1 spells out habitability of a residence). They might attempt to physically removing you, which is a crime -- battery -- and Cal. Civ. Code 1940.2 and 1942.5 says that landlords cannot threaten force, invade the premise, and so on, with substantial penalties for violation of that law. Staying within the bounds of the law, a landlord cannot just throw you out: there is a legal eviction process. If you engage in certain activities, you can be legally tossed out (look around p. 76 here). Otherwise, your lease is a contract which the courts will enforce, even though the landlord might wish that he could terminate the contract.