Unravelling a new many-body large-hole polaron in a transition metal oxide that promotes high photocatalytic activity

A many-body large polaron, crucial for fundamental physics and technological applications, was predicted in bismuth vanadate (BiVO₄). This research reveals a new many-body large-hole polaron in W-doped BiVO₄ films using high-resolution spectroscopic ellipsometry, X-ray absorption spectroscopy, and high-resolution X-ray diffraction, supported by theoretical calculations. Anomalous spectral weight transfers reveal electronic correlations and screening. The large-hole polaron forms as a localized midgap state, impacting BiVO₄'s high photocatalytic activity. The interplay between the large-hole polaron and indirect bandgap is key to this activity, highlighting the importance of charge, orbital, and lattice degrees of freedom.

Xiao Chi, Lily Mandal, Cuibo Liu, Angga Dito Fauzi, Anindita Chaudhuri, Thomas J. Whitcher, Hariom Kirit Jani, Zhongxin Chen, Shibo Xi, Caozheng Diao, Muhammad Avicenna Naradipa, Xiaojiang Yu, Ping Yang, Antonio Helio Castro-Neto, Mark B. H. Breese, Kian Ping Loh, Thirumalai Venky Venkatesan, Andrivo Rusydi