hammer curls are for training the brachialis, which underlies the biceps. if it makes your bicep sit higher then that may be thought of as "peak". but no exercise will specifically grow one area of a muscle.
big nate is right...... you cant isolate half of a muscle...... genetics are the factor here....... but take the hammer approach to hit the brachaliss ........ it sits deep in the arm between the bi and tri....... when full developed it looks like there is 3 muslce on the outside of the arm...... that sounds like the area you are describing.