title: Hidden phase in a two-dimensional Sn layer stabilized by modulation hole doping.
abstract: Semiconductor surfaces and ultrathin interfaces exhibit an interesting variety of two-dimensional quantum matter phases, such as charge density waves, spin density waves and superconducting condensates. Yet, the electronic properties of these broken symmetry phases are extremely difficult to control due to the inherent difficulty of doping a strictly two-dimensional material without introducing chemical disorder. Here we successfully exploit a modulation doping scheme to uncover, in conjunction with a scanning tunnelling microscope tip-assist, a hidden equilibrium phase in a hole-doped bilayer of Sn on Si(111). This new phase is intrinsically phase separated into insulating domains with polar and nonpolar symmetries. Its formation involves a spontaneous symmetry breaking process that appears to be electronically driven, notwithstanding the lack of metallicity in this system. This modulation doping approach allows access to novel phases of matter, promising new avenues for exploring competing quantum matter phases on a silicon platform.
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: Fangfei
authors.initials: F
authors.lastname: Ming
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mulugeta
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: Weisong
authors.initials: W
authors.lastname: Tu
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: Tyler S
authors.initials: TS
authors.lastname: Smith
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA.|Joint Institute for Advanced Materials at The University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: Paolo
authors.initials: P
authors.lastname: Vilmercati
authors.affiliation: Department of Physics, Inha University, Inchon 402-751, Korea.
authors.forename: Geunseop
authors.initials: G
authors.lastname: Lee
authors.affiliation: Department of Physics, Penn State University, University Park, Pennsylvania 16802, USA.
authors.forename: Ying-Tzu
authors.initials: YT
authors.lastname: Huang
authors.affiliation: Department of Physics, Penn State University, University Park, Pennsylvania 16802, USA.
authors.forename: Renee D
authors.initials: RD
authors.lastname: Diehl
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA.|Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Paul C
authors.identifier: 0000-0003-1194-1925
authors.initials: PC
authors.lastname: Snijders
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA.|Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Hanno H
authors.initials: HH
authors.lastname: Weitering