The sear is definitely where the problem lies. Too long by far.
Cast iron is the best option, but if not that other things that will take very high heat are good. Stainless steel is not good. Put the pan on to heat before you remove the steak from it's package. Dry the steak well and salt 'n' pepper. When the pan starts to smoke apply a little high smoke-point oil and allow a little time for the temperature to rise a bit further before adding the steak to the pan.
Searing in a perfect world should take around 30 seconds per side, but certainly less than a minute each side.
NB: Open windows may be advisable.