We report the first results of a high-redshift (z>~5) quasar survey using the Dark Energy Spectroscopic Instrument (DESI). As a DESI secondary target program, this survey is designed to carry out a systematic search and investigation of quasars at 4.8<z<6.8. The target selection is based on the DESI Legacy Imaging Surveys (the Legacy Surveys) DR9 photometry, combined with the Pan-STARRS1 data and J-band photometry from public surveys. A first quasar sample has been constructed from the DESI Survey Validation 3 (SV3) and first-year observations until 2022 May. This sample includes more than 400 new quasars at redshift 4.7<=z=5, more than one-third of existing quasars previously published at this redshift. The observations so far result in an average success rate of 23% at z>4.7. The current spectral data set has already allowed analysis of interesting individual objects (e.g., quasars with damped Ly{alpha} absorbers and broad absorption line features), and statistical analysis will follow the survey's completion. A set of science projects will be carried out leveraging this program, including quasar luminosity function, quasar clustering, intergalactic medium, quasar spectral properties, intervening absorbers, and properties of early supermassive black holes. Additionally, a sample of 38 new quasars at z~3.8-5.7 discovered from a pilot survey in the DESI SV1 is also published in this paper.

Cone search capability for table J/ApJS/269/27/table1 (The 412 new quasars from our main selection)

Cone search capability for table J/ApJS/269/27/table2 (The 38 new quasars from the selection during the DESI first Survey Validation (SV1) between 2020-Dec and 2021-May)