title: Tuning magnetotransport in a compensated semimetal at the atomic scale.
abstract: Either in bulk form, or in atomically thin crystals, layered transition metal dichalcogenides continuously reveal new phenomena. The latest example is 1T'-WTe2, a semimetal found to exhibit the largest known magnetoresistance in the bulk, and predicted to become a topological insulator in strained monolayers. Here we show that reducing the thickness through exfoliation enables the electronic properties of WTe2 to be tuned, which allows us to identify the mechanisms responsible for the observed magnetotransport down to the atomic scale. The longitudinal resistance and the unconventional magnetic field dependence of the Hall resistance are reproduced quantitatively by a classical two-band model for crystals as thin as six monolayers, whereas a crossover to an Anderson insulator occurs for thinner crystals. Besides establishing the origin of the magnetoresistance of WTe2, our results represent a complete validation of the classical theory for two-band electron-hole transport, and indicate that atomically thin WTe2 layers remain gapless semimetals.
authors.affiliation: Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.|Group of Applied Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.|Group of Applied Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Gutiérrez-Lezama
authors.affiliation: Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.
authors.forename: Céline
authors.initials: C
authors.lastname: Barreteau
authors.affiliation: Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.|Group of Applied Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ubrig
authors.affiliation: Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.
authors.forename: Enrico
authors.initials: E
authors.lastname: Giannini
authors.affiliation: Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.|Group of Applied Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.
authors.forename: Alberto F
authors.initials: AF
authors.lastname: Morpurgo