TY - JOUR AU - Kathryn AU - Yiming Qiu AU - John Copley AU - H. AU - B. C2 - Physical Review Letters DA - 2014-02-04 LA - en M1 - 112 PB - Physical Review Letters PY - 2014 TI - Order by Disorder Spin Wave Gap in the XY Pyrochlore Magnet Er2Ti2O7 UR - https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=914620 ER -