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arXiv · 1509.03623

Breakdown of compensation and persistence of non-saturating magnetoresistance in WTe2 thin flakes

Yilin Wang·Kefeng Wang·Janice Reutt-Robey·Johnpierre Paglione·Michael S. Fuhrer
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Abstract

We present a detailed study of magnetoresistance \r{ho}xx(H), Hall effect \r{ho}xy(H), and electrolyte gating effect in thin (<100 nm) exfoliated crystals of WTe2. We observe quantum oscillations in H of both \r{ho}xx(H) and \r{ho}xy(H), and identify four oscillation frequencies consistent with previous reports in thick crystals. \r{ho}xy(H) is linear in H at low H consistent with near-perfect electron-hole compensation, however becomes nonlinear and changes sign with increasing H, implying a breakdown of compensation. A field-dependent ratio of carrier concentrations p/n can consistently explain \r{ho}xx(H) and \r{ho}xy(H) within a two-fluid model. We also employ an electrolytic gate to highly electron-dope WTe2 with Li. The non-saturating \r{ho}xx(H) persists to H = 14 T with magnetoresistance ratio exceeding 2 x 104 %, even with significant deviation from perfect electron-hole compensation (p/n = 0.84), where the two-fluid model predicts a saturating \r{ho}xx(H). Our results suggest electron-hole compensation is not the mechanism for extremely large magnetoresistance in WTe2, other alternative explanations need to be considered.

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Yilin Wang, Kefeng Wang, Janice Reutt-Robey, Johnpierre Paglione, Michael S. Fuhrer. 2015-09-11. Breakdown of compensation and persistence of non-saturating magnetoresistance in WTe2 thin flakes. https://doi.org/10.1103/physrevb.93.121108

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