Electrons in surface states on liquid helium

Grimes, C. C.

doi:10.1016/0039-6028(78)90517-4

Cited by 149 publications

(30 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Electrons on a surface of liquid helium represent a remarkable 2D electronic system with parameters strongly different from those of 2DEGs in semiconductor structures, see Andrei (1997); Grimes (1978); Monarkha and Kono (2004) for reviews. First, because of a very low density, correlations play an essential role: in the zero-temperature limit this system would be a Wigner crystal.…”

Section: Electrons On Liquid Heliummentioning

confidence: 99%

Nonequilibrium phenomena in high Landau levels

et al. 2012

View full text Add to dashboard Cite

Developments in the physics of 2D electron systems during the last decade revealed a new class of nonequilibrium phenomena in the presence of a moderately strong magnetic field. The hallmark of these phenomena is magnetoresistance oscillations generated by the external forces that drive the electron system out of equilibrium. The rich set of dramatic phenomena of this kind, discovered in high mobility semiconductor nanostructures, includes, in particular, microwave radiation-induced resistance oscillations and zero-resistance states, as well as Hall field-induced resistance oscillations and associated zero-differential resistance states. The experimental manifestations of these phenomena and the unified theoretical framework for describing them in terms of a quantum kinetic equation are reviewed. This survey also contains a thorough discussion of the magnetotransport properties of 2D electrons in the linear-response regime, as well as an outlook on future directions, including related nonequilibrium phenomena in other 2D electron systems.

show abstract

Section: Electrons On Liquid Heliummentioning

confidence: 99%

Nonequilibrium phenomena in high Landau levels

et al. 2012

View full text Add to dashboard Cite

show abstract

“…We demonstrate, by appealing to theoretical arguments and ab initio calculations, that the reduction in E-field is caused primarily by transformation of the quartz into a negative electron affinity (NEA) surface via adsorption of Rb atoms on the surface. A NEA surface can bind electrons, similar to the image potential states on liquid helium (LHe) [31][32][33]. While the surface repulsion for electrons on LHe is provided by Pauli blocking, the repulsion on quartz occurs because the surface vacuum level dips below the bottom of the conduction band.…”

mentioning

confidence: 99%

Electric Field Cancellation on Quartz by Rb Adsorbate-Induced Negative Electron Affinity

et al. 2016

View full text Add to dashboard Cite

We investigate the (0001) surface of single crystal quartz with a submonolayer of Rb adsorbates. Using Rydberg atom electromagnetically induced transparency, we investigate the electric fields resulting from Rb adsorbed on the quartz surface, and measure the activation energy of the Rb adsorbates. We show that the adsorbed Rb induces a negative electron affinity (NEA) on the quartz surface. The NEA surface allows low energy electrons to bind to the surface and cancel the electric field from the Rb adsorbates. Our results are important for integrating Rydberg atoms into hybrid quantum systems and the fundamental study of atom-surface interactions, as well as applications for electrons bound to a 2D surface.Due to recent technological advances in fabrication and trapping, hybrid quantum systems (HQS) consisting of atoms and surfaces, as well as electrons and surfaces, are fast emerging as ideal platforms for a diverse range of studies in quantum control, quantum simulation and computing, strongly correlated systems and microscopic probes of surfaces. Miniaturization of chip surfaces is necessary to achieve large platform scalability, but decoherence and noise emerge as serious challenges as feature sizes shrink [1][2][3]. Mitigating the noise is a fundamental and necessary step in realizing the full potential of HQSs for quantum technologies.Combining ultracold Rydberg atoms with surfaces for HQS is attractive because Rydberg atoms can have large sizes, significant electric dipole moments and strong interactions. There have recently been a host of theoretical proposals for utilizing Rydberg atoms near surfaces [4][5][6][7][8]. Progress on the experimental front has been hampered by uncertainties in characterizing interactions of atoms with surfaces, although some recent work in this regards are noteworthy [9][10][11].To take full advantage of Rydberg atom HQSs, a more complete understanding of surfaces is needed. One problem is that Rydberg atoms incident upon metal surfaces can be ionized [12, 13]. A second major hurdle is the background electric fields (Efields) caused by adsorbates [14][15][16][17][18][19]. Rydberg states are sensitive to adsorbate E-fields because they are highly polarizable [20]. Adsorbate E-fields have caused problems for other experiments as well, including Casimir-Polder measurements [21], and surface ion traps [22]. A possible solution is to minimize the E-fields by canceling them out.A convenient surface for applications in HQSs is quartz because of its extensive use in the semiconductor and optics industries. Despite numerous theoretical and experimental studies of bulk SiO 2 [23-25], the surface properties are not well understood. Recent theoretical work has focused on surface reconstruction and the adsorption of water and graphene [26][27][28][29][30]. The (0001) surface has been the subject of recent theoretical interest, partially due to its stability and low surface energy [26,30].In this work, we show that adsorption of Rb atoms on a quartz (SiO 2 (0001)) surface, contrary to prev...

show abstract

“…Experimental results are then described that cannot be explained by the previous emission mechanisms. A mechanism is proposed that combines the high electric fields that can be obtained at the intersection of a semiconductor surface, a metal substrate and vacuum (a so-called triple junction) 7,8 with the mobile electron surface states that form on NEA surfaces 9,10 . Cathodes fabricated to maximize the triple junction-NEA surface-emission mechanism, referred to here as surface emission cathodes, emit measurable currents (10 −10 A cm −2 ) at gate voltages of 3 to 4 V, and useful current densities (Ͼ1 mA cm −2 ) at 6 to 10 V. In some cases, these electrons are emitted as a collimated beam of nearly monoenergetic electrons.…”

mentioning

confidence: 99%

A new surface electron-emission mechanism in diamond cathodes

Geis

Efremow

Krohn

et al. 1998

Nature

235

138

View full text Add to dashboard Cite

An electron-emission mechanism for cold cathodes is described based on the enhancement of electric fields at metaldiamond-vacuum triple junctions. Unlike conventional mechanisms, in which electrons tunnel from a metal or semiconductor directly into vacuum, the electrons here tunnel from a metal into diamond surface states, where they are accelerated to energies sufficient to be ejected into vacuum. Diamond cathodes designed to optimize this mechanism exhibit some of the lowest operational voltages achieved so far.Conventional cathodes for applications from television to power transmitters use heat to boil electrons out of a metal into vacuum. However, these cathodes do not have the power efficiency or the dimensional stability to be used with micrometre-size structures, which are required for flat-panel displays and some power amplifiers. Cathodes that can be scaled to micrometre sizes use high electric fields instead of heat to pull electrons out of a solid into vacuum. The reliability and current density of these electric field emission cathodes depend upon both their geometry and the material used in their construction. Here we review field emission cathodes and show that a new cathode geometry which uses a novel material, diamond, has properties superior to those of previous cathodes.For the cold cathodes we discuss, emission is obtained with a large electric field that causes electrons to tunnel over a potential barrier out of a metal substrate into vacuum. Material and fabrication techniques have both been used to increase emission by enhancing the electric field and reducing the barrier over which the electrons must tunnel. Excellent low electric field electron emission has been reported from diamond and amorphous diamond-like films on metal substrates, but practical application of these cathodes is limited by a serious lack of reproducibility 1-3 and inconsistency (M. E. Kordesch, personal communications). Emission originates from a few localized sites, which were believed to be due to the inconsistent bulk properties of the cathode material. The enhanced emission at the interface between the diamond surface, a conductive region, and vacuum, a new emission mechanism, may explain the localization of emission sites. If so, a discontinuous diamond film that provides an abundance of interfaces should be a better electron emitter than a continuous diamond film 4,5 .We now describe two generally accepted emission mechanisms: geometric electric-field enhancement 6 , and Schottky diode with a negative-electron-affinity semiconductor 2,3 . Semiconductors and insulators have a negative electron affinity (NEA) if the minimum energy of electrons in the conduction band is above the minimum energy of electrons in vacuum. Experimental results are then described that cannot be explained by the previous emission mechanisms. A mechanism is proposed that combines the high electric fields that can be obtained at the intersection of a semiconductor surface, a metal substrate and vacuum (a so-called triple junction) 7,8 with t...

show abstract

Electrons in surface states on liquid helium

Cited by 149 publications

References 51 publications

Nonequilibrium phenomena in high Landau levels

Nonequilibrium phenomena in high Landau levels

Electric Field Cancellation on Quartz by Rb Adsorbate-Induced Negative Electron Affinity

A new surface electron-emission mechanism in diamond cathodes

Contact Info

Product

Resources

About