The peak of something is the highest point or level:
The hikers reached the mountain’s peak in four hours.
Home values in my neighborhood reached their peak five years ago.
Pique, pronounced the same as peak, is derived from the French word piquer, which means literally “to prick.” “To pique” is to excite or arouse, and it is most often used with the words interest or curiosity:
The front page headline piqued my interest in the news story.
Often writers will mistakenly use peak when they mean pique. The confusion likely stems from an incorrect assumption that because peak and pique sound the same, they are also spelled the same. Also, peak is the more common word.
The front page headline peaked [incorrect] my interest in the news story.