Semi-classical origin of the extreme magnetoresistance in PtSn<sub>4</sub>.

Diaz, J; Wang, K; Straquadine, J; Putzke, C; Yang, Qun; Yan, Binghai; Bud'ko, S L; Canfield, P C et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

The so-called "extreme magnetoresistance" (XMR) found in few conductors poses interesting conceptual challenges which address needs in technology. In contrast to the more common XMR in semi-metals, PtSn<sub>4</sub> stands out as a rare example of a high carrier density multi-band metal exhibiting XMR, sparking an active debate about its microscopic origin. Here we report a sharp sensitivity of its XMR upon the field angle, with an almost complete collapse only for one specific current and field direction (B//b, I//a). Corroborated by band-structure calculations, we identify a singular open orbit on one of its Fermi surface sheets as the origin of this collapse. This remarkably switchable XMR resolves the puzzle in PtSn<sub>4</sub> as a semi-classical effect of an ultra-pure, compensated carrier metal. It further showcases the importance of Ockham's razor in uncommon magnetotransport phenomena and demonstrates the remarkable physical properties conventional metals can exhibit given they are superbly clean.