He authored many works based on his extensive study of the Matenadaran's materials and other sources, notably publishing multiple compilations of 14th and 15th century Armenian colophons.

[3] After graduating from Khachatur Abovian High School in 1935, he enrolled in the Faculty of History at Yerevan State University.

[4] Immediately after graduating from university in 1940, he joined the staff of the Mashtots Matenadaran, first as a bibliographer, then as manager of the manuscript archive.

[5][6] In 1945, he successfully defended his dissertation titled Yeghishei "Araratsots’ meknut’iwnë" (Elishe's "Interpretation of Genesis", published as a book in 1993)[7] and received the degree of Candidate of Historical Sciences.

[3] From 1951 to 1954, he worked at the Institute of History of the Academy of Sciences of the Armenian SSR, first as a senior researcher, then as the head of its publications department.

[8] Khachikyan wrote many works on medieval Armenian history based on his extensive study of manuscript materials.

Among his major works on these subjects are the book P’ok’r Hayk’i sots’ialakan sharzhumneri patmut’yunits’ (From the history of the social movements of Armenia Minor, 1951) and the articles "XIV-XV dareri haykakan gyughakan hamaynk’i masin" (On the 14th–15th-century Armenian village community, 1958), and "Yerznka k’aghak’i 'Yeghbarts’ miabanut’ean' kanonadrut’yunë" (The charter of the 'Order of Brothers' of the city of Erznka, 1962).

[2] His main period of interest was the late medieval period (14th–15th centuries), although a number of his works are dedicated to early medieval Armenian history, such as the aforementioned P’ok’r Hayk’i sots’ialakan sharzhumneri patmut’yunits’ and the articles "Otaralezu hay grakanut’yunë IV darum" (Foreign-language Armenian literature in the 4th century), and "Nakhamesropyan gri harts’ë yev hmayagrerë" (The question of pre-Mesropian writing and the charms).

[6][4] In the course of his research, he discovered important information about the social and economic life of medieval Armenia, the activities of monastic schools, centers of manuscript production and scholarship.

[9][17] He was posthumously awarded the State Prize of the Armenian SSR for his contributions to the work Hay zhoghovrdi patmut’yun.