The S&P 500 ended lower on Tuesday, weighed down by losses in Micron Technology and other chipmakers due to mounting doubts about the sustainability of Wall Street’s AI-driven rally. Chip stocks in Asia and the United States dropped after memory chip giant Samsung Electronics’ (005930.KS), opens new tab blowout earnings report failed to satisfy investors with sky-high expectations. Micron (MU.O), and Sandisk (SNDK.O), both fell, pulling the PHLX chip index (.SOX), lower. Adding to worries…