What are the gothic elements present in The Scarlet Letter?

Though Nathaniel Hawthorne's 1850 novel is generally considered Romantic, the author did incorporate elements of the American gothic genre, particularly with regard to dark themes of sin, guilt, and psychological torment.
Arthur Dimmesdale's obsession with what he considers the greatest sin of his life, fathering Pearl outside marriage, destroys his physical and psychological health. He lacks the courage to face the judgment of his Puritan congregation by confessing his sin. Consequently, he holds secret his feelings of guilt and punishes himself for years until he ultimately collapses and dies.
Roger (Prynne) Chillingworth also suffers psychologically; his masculine pride will not allow him to claim Hester Prynne as his wife after she has given birth to Pearl. His love for her remains unrequited until his death, and the only pleasure he seems to get from his existence is through exacting his revenge on the man who cuckolded him. His psychological torment of Dimmesdale adds to the misery of both the fallen minister and his lover, Hester.
And lastly, gothic fiction usually contains a supernatural element. Pearl Prynne's precociousness borders on something unnatural; she is often compared to an imp, a not-quite-human child. She senses her connection to her mother's badge of shame in a manner that seems supernatural.